improvement in the rendering into English of the matter already employed. In the direction of chemico-botanical research there is great room for investigation, and a text-book embracing the knowledge already acquired, and information on points in connection with the chemistry of vegetable physiology, would render such a work of interest not only to the scientific chemist or botanist, but also to the general reader. Baron von Mueller's translation forms an excellent nucleus for such a work, and should a future edition of the book be required, we should hope to find it enlarged in such directions.

J. M. T.

GEOGRAPHICAL ASTRONOMY

Abriss der praktischen Astronomie, vorzüglich in ihrer Anwendung auf geographische Ortsbestimmung. Von Dr. A. Sawitsch, nach der zweiten russischen OriginalAusgabe. Neu herausgegeben von Dr. C. F. W. Peters. (Leipzig, 1879.)

S may be inferred from the title of this work, the astronomical reader will not find it to be a general treatise on the practical branches of the science, but one confined to the theory and uses of instruments, and explanation of methods employed at the present day in the determinations of geographical positions. As such the name of its author, Dr. A. Sawitsch, the well-known Professor of Astronomy in the Imperial University of St. Petersburg, will give the work high recommendation in the estimation of the student. The two volumes of the original edition are now incorporated in one, and such modifications as have been rendered necessary by the introduction of new or improved forms of instruments, and refinements of observation and reduction have been introduced in a great measure by the author himself. In the opening chapter we have explanations of the various methods of reckoning time, and the transformation of one into another; the reduction of mean into apparent places, the calculation of refraction and parallax, and the influence of the earth's compression upon the geocentric co-ordinates of points upon the surface, with remarks upon angular measures in general, and upon the astronomical telescope and its adjustment, the microscopes, verniers, level, &c. In the first section, the author treats of the transit instrument, and enters into the various adjustments to which it is subjected, and also describes in some detail the universal instrument of Piston and Martins, and the errors of division to which instruments for angular measures may be liable. second section is devoted to the determination of latitude and time by measure of zenith distance, of time from corresponding altitudes, &c. The third section enters more fully into the uses and theory of the transit instrument, and likewise describes Bessel's method for the determination of latitude thereby, supplying practical rules and an example. The next section treats of the determination of azimuth, and of the influence of diurnal aberration on the polar co-ordinates of a star. The fifth section contains a valuable outline of the various methods

The

applicable to the determination of terrestrial longitude, including the telegraphic method, the transportation of chronometers, and longitude by observations of eclipses, especially those of the sun, and by lunar occultations.

The reference to the utility of eclipses for longitudedetermination leads to an important chapter on Hansen's method for the calculation of the general circumstances of these phenomena upon the earth's surface, and the methods followed by Dr. Zech, in his researches on the historical eclipses; and, as a numerical example, the formulæ are applied to the computation of the circumstances of the total solar eclipse of August 18, 1887, to which frequent reference has been made in astronomical treatises. The data are founded upon the lunar tables of Hansen and the solar tables of Leverrier. Further, we have a discussion on moon-culminators in their application to longitudes, with notices on the methods of Nicolai and Struve, and a fully-worked-out example. The sixth section relates to the reduction of the longitude, latitude, and azimuth of a place to another, both accurately and approximately, and the determination of the distance of points on the terrestrial spheroid, of which the geographical positions are given. There are two supplementary chapters: the one bearing upon reflectioninstruments, and of course entering at length into the use of the sextant; the other treating of interpolation, with special reference to the formulæ of Bessel and Hansen.

In the language in which this work originally appeared it would be almost a sealed book in Western Europe. The excellent translation into a language of which every scientific student should, in these days, possess a knowledge, now placed in our hands by Dr. Peters, will be, without doubt, a welcome addition to his means of instruction on an important branch of practical astronomy.

OUR BOOK SHELF

A Treatise on Dynamics of a Particle, with numerous Examples. By P. G. Tait and the late W. J. Steele. Fourth Edition. (London: Macmillan and Co., 1878.) THE bibliography of this revised text-book is a first edition in 1856, 304 pages; a second edition in 1865, 363 pages; a third edition in 1871, 428 pages; and the present disposition and amount of the matter in this edition, edition of 407 pages. There are slight alterations in the caps. x. and xi. of the third are put into cap. ix., caps. v. and vi. are contained in cap. v. of the fourth. The position of some of the exercises has been changed. The main features remain unaltered. The revision has had the advantage of Prof. Greenhill's supervision, who has verified (and corrected where necessary) the Examples and has freely introduced the use of Elliptic Functions. There is no need of any commendation for a text-book so well-known. We are, however, very much disposed to think that had Prof. Tait composed the work at a later date than he did, it would have differed somewhat from its present form and have approximated more closely to the Natural Philosophy brought out under the joint editorship of Sir William Thomson and himself. The author justly complains that "several sections in which some novelties appear have been translated almost letter for letter and transferred, without the slightest allusion to their source, to the pages of a German work. Several other books have obviously been similarly treated. It is well that this should be known, as the English authors might otherwise come to be supposed to have adopted these passages simpliciter from the German." Familiar Wild Flowers. Figured and Described by F. Edward Hulme, F.L.S., F.S.A. First Series. With Coloured Plates. (Cassell, Petter, and Galpin.) SCIENTIFIC books are of three kinds: to inform the

scientific world of some fresh discovery or advance works of research; to offer a digest, for the information of students, of results already attained-text-books; and to attract to the paths of science the outside public popular works. The pretty and attractive book before us belongs to the last of these categories, and is, we think, well calculated to gain the end in view. It consists of chromo-lithographs of nearly fifty of our better-known native wild flowers, with two or three pages of gossipy talk about each. Of the letter-press not much more can be said than that it is fairly accurate from a botanical point of view, and pleasantly written. The illustrations strike us as unusually good of their kind. They have of course the inherent defects of this mode of illustration, in the absence of half-tones and delicate shades; but the general aspect of the plant is in nearly all cases well and faithfully given, and the drawing is good. The book is a very good one to put in the hands of a child to interest him or her in the wealth of wild flowers which is such a source of delight to all dwellers in the country who have eyes educated to see their beauty.

LETTERS TO THE EDITOR

[The Editor does not hold himself responsible for opinions expressed by his correspondents. Neither can he undertake to return, or to correspond with the writers of, rejected manuscripts. No notice is taken of anonymous communications. [The Editor urgently requests correspondents to keep their letters as short as possible. The pressure on his space is so great that it is impossible otherwise to ensure the appearance even of com munications containing interesting and novel facts.]

The Telephone

I HAVE just read an article in NATURE, vol. xviii. p. 698, on the history of the speaking telephone, which contains an erroneous statement of facts which happen to be within my own knowledge; so that, in the interest of a truthful history of this discovery, it is incumbent upon me to make a brief statement in regard to it.

I had the honour to be one of the judges at the International Exhibition at Philadelphia, and of the group to whom was confided the examination of instruments of research and precision. In the performance of my official duty I took part in the experiments which first brought the speaking telephone to the notice of the scientific world. Prof. Bell and Mr. Elisha Gray were both exhibitors at that Exhibition. Mr. Gray's apparatus was conspicuously shown near one of the main aisles, with the exhibit of the Western Electric Company, while Prof. Bell's was in a side room in one of the galleries, as a part of the Massachusetts' educational exhibit. About the middle of June, 1876, Prof. Bell came to Philadelphia to give personal explanations in reference to his apparatus, and before any public exhibition was made he stated to me in detail the character of his inventions. He was working at two independent things, the one the multiple telegraph by means of transmitted musical notes, the other the transmission of articulate speech over long distances. I told him that I was present in May, 1874, at the rooms of Prof. Henry, in the Smithsonian Institution, when Mr. Elisha Gray exhibited to us an apparatus for the electric transmission of musical sounds, and I asked him whether his first invention was similar. He said there was some similarity, although each had worked independently, and that there was a dispute as to the priority of invention. While sanguine as to practical results from his multiple telegraph, his great invention was the speaking telephone, which he believed he had discovered, and in respect to which there was no rival claimant. He said the idea came to him from some of the suggestions in respect to sound vibrations made by Helmholtz, and that he had succeeded, after patient research, in constructing an instrument which would transmit articulate speech. To this invention he desired to direct the attention of the judges.

The experiments with the telephones had to be made when the Exhibition was closed to the public, and the first experiments were made by Sir William Thomson and others on Sunday, June 18 or 25-I do not now remember upon which of these two dates. Their Majesties the Emperor and Empress of Brazil were present at these experiments. Attention was first given to Mr.

Gray, and he gave a lengthy account of his experiments, which had resulted in the perfected apparatus which he then exhibited. He gave an explanation of his various instruments in chronological order, and conducted some very entertaining experiments as he proceeded in his discourse. The object which he had in view was to send many messages simultaneously over the same musical notes. wire by using sending and receiving instruments of different

The greater part of the day was given to Mr. Gray, so that insufficient time remained for satisfactory trial of Prof. Bell's apparatus. The judges and the distinguished visitors present did, however, proceed to the Massachusetts gallery, and Prof. Bell explained briefly his two inventions, and some experiments were made with his speaking telephone, enough to excite the curiosity of those present in the highest degree. The results were so at variance with the views hitherto received that it was determined by my distinguished colleague, Sir William Thomson, to make other experiments, in which I took part. These experiments were made two or three days later, in the building known as the Judges' Pavilion, in the evening, after the visitors had left the grounds. Prof. Bell had returned to Boston, and was not present at this trial of his apparatus. It was brought over to the judges' pavilion, at my request, by Mr. Hubbard, one of the officers in charge of the Massachusetts exhibit, and the experiments were made by Sir William Thomson and myself. Every precaution was taken to make an impartial test. I was at the transmitting instrument which was placed out of doors at a distant part of the building, and Sir William Thomson was at the receiving instrument in a distant room in the building. After some experiments to find the pitch of voice which would suit the vibrating membrane then used, I received word by messenger from Sir William that he could then hear distinctly, and accordingly the pitch of voice then used was maintained in the subsequent trials. I held in my hand a copy of the New York Daily Tribune, and I began to read to him items from its news summary, and soon the messenger came to tell me that the messages were heard distinctly at the other end. The longest message which I sent was the following from that paper :"The Americans of London have made arrangements to celebrate the coming Fourth of July," and the messenger brought me back from Sir William Thomson the exact repetition of the message. Thereupon we exchanged places, and I could not only hear distinctly the utterances of my colleague, but I could even distinguish the ictus of his voice. The results convinced both of us that Prof. Bell had made a wonderful discovery, and that its complete development would follow in the near future.

The news of these successful experiments soon circulated freely, and the day following, or possibly two days afterwards, Mr. Gray came to me and inquired whether the reports of our success with Bell's telephone were correct; and upon receiving from me an affirmative reply, he said that it was impossible, that we had been deceived in some way, that the transmission was by actual metallic contact through the wire, and that it was, to use his own words, "nothing more than the old lover's telegraph." In reply I said to him that we had taken every possible precaution against error, that we were both convinced of the reality of Bell's claims, and that Sir William Thomson would report to that effect. He persisted in his statement that the result was impossible, and that we must have been deceived in some way or other.

After having had direct knowledge of Mr. Gray's views at that time, I must confess to some astonishment at his claim now made that he anticipated Mr. Bell in the invention of the speaking telephone. Several months ago I saw an article in Scribner's Magazine, by Mr. Prescott, in which, while no direct assertion was made that Mr. Gray was the first inventor, there were illustrations given to show the development of the invention in chronological order, and Mr. Gray's instrument was there given priority. I had it in mind then to write a note to Mr. Prescott upon this subject, but I feared that there might be unpleasant controversies over the patents, and, the claim of Mr. Gray being rather indefinitely stated, I held my peace. But now that the error appears to be taking root, I have felt it to be my duty to make the statements above given. I have before me a letter from Mr. Bell, dated at Boston, Wednesday, June 28, 1876, and directed to me at Philadelphia, in which he gives diagrams showing how we might arrange the apparatus to transmit articulate speech, as he believed, from Boston to Philadelphia, and proposing experiments to that end if the judges should so desire. In conclusion I ought to state further, that after Sir William Thomson's address at Glasgow had brought the telephone into

notoriety, Mr. Gray, whose instruments had also been called telephones, gave a public exhibition, in Chicago, I think, and in the report of his lecture which I read, he never once alluded to Bell's invention. His discourse was then, as at Philadelphia before the judges, solely in reference to the musical telephone. In fact, the newspapers had to take pains to inform the public that Mr. Gray's invention must not be confounded with Mr. Bell's, to which Sir William Thomson had referred. You will imagine, then, the surprise of the judges who examined these inventions particularly at Philadelphia in 1876, and heard the personal explanations made by the inventors, to be told now that Gray had already invented the speaking telephone, when all his statements then made show directly to the contrary. Ann Arbor, November 18 JAMES C. WATSON

The Intra-Mercurial Planets NATURE (vol. xviii. p. 569), in commenting upon my letter published the previous week, regarding the discovery of Vulcan, accused me of being not only "indefinite," but "contradictory.' The number containing my letter (p. 539) has, from some unknown cause, not yet reached me, though I am in receipt of four numbers published later.

In the several articles written by me on that subject to the Chicago Astronomical Society, to the Naval Observatory at Washington, to the Astronomer-Royal, to Admiral Muochez of the Paris Observatory, and to others-I have invariably stated the facts as they occurred under my observation, and as they impressed themselves upon my mind, and have invariably adhered to these statements, viz., that the two stars seen by me were of about the fifth magnitude, about 7' or 8' apart, with large red disks, and pointing towards the sun's centre. It is true my letter did contain an error, but not of observation, nor of estimation. In reducing the 8' of arc (the estimated distance between the stars) to time, I somehow called it 2', when, in reality, it is but 32s., thus not only changing its position in R.A, but also increasing, in this element, the discordance between Prof. Watson and myself. The detection of this error has changed, to me, the whole aspect of the Vulcan question. I had previously written to Prof. Watson that I could not reconcile his observations with my own either in R. A., or in Dec., but did not tell him what changes were necessary in order that they might harmonise. He gave me his corrected positions, which helped matters considerably, but still his R.A. was too great, and Dec. too little, for, from three estimations, the two stars ranged with the sun's centre. Recently I have been experimenting with a and a2 Capricorni (two stars which, in respect to distance from each other, resemble those I saw during the eclipse), my object being to test the accuracy of estimations made of the directions towards which two stars will range when hastily brought into the estimated centre of the field of a telescope having a diameter of one and a half degrees. I find that unless the objects are brought exactly to the centre, they do not point to the same place. During totality time was, of course, too precious to waste in being precise in this, and yet I endeavoured to be so, and as at each of the three comparisons they seemed to range with the sun's-centre, I feel convinced that I was not far out in my estimated Dec.

In order to meet Prof. Watson's excessive R.A., I published (contrary, however, to my better judgment), that the distance between the stars was about 8' instead of 7' (as previously announced). On the assumption, therefore, that (a) one of the objects was Cancri, and (6) that they were 8' apart, and (c) that the one nearest the sun was the planet, as Watson says, the position of the planet was as follows:

Washington M. T. 1878, July 29, 5h. 22 m. R.A., ◊ Cancri

Add 8' =

...

8h. 24m. 40s. 32s. Sh. 25m. 125. 8h. 27m. 35s.

2m. 23s. 18° 30'

18° 16'

14'

It will be seen that there is a discrepancy between us of over a half degree of arc in R.A. If we saw the same objects how can we differ so widely? Could I be in error to the amount of 34' between two stars in the same field? Can two stars be three

and one half times the distance of Mizar from Alcor and an observer of experience estimate them at only 7' or 8'? It will be remembered that I recorded in my note-book at the time the distance as 12', but knowing how liable I might be to error in the valuation of so large a distance (for though, from practice, I can estimate quite closely double stars whose distances are from 2" to 20", I have had no experience in the estimation of those of several minutes separation), I chose to carry it in my mind until I should reach home, when it would be the work of only a few minutes to find two stars of the same apparent distance.

I said to Prof. Hough on our homeward journey, that, from memory, I thought their distance was about equal to that separating a and a Capricorni, and that I could decide when I should observe them. My memory of Mizar and Alcor was quite distinct, and as soon as I thought of those (which I did before my arrival at Kansas City) I mentally said, "A little over half the distance between them equals that between 0 Cancri and the new object, which I did not doubt was Vulcan. Upon my arrival at home I immediately consulted "Webb's Celestial Objects," and was not a little surprised to find their whole distance to be less than 12'. Thus I know they were not over 8' apart, I believe they were but 7'. I know they pointed to the sun's disk, I believe they did to his centre. I know they did not differ one-fourth of a magnitude in brightness, I believe they were exactly equal. I see them, in my mind's eye, as I then saw them, and, while consciousness endures, their image can never fade from the retina of my memory!

I consider the estimated distance in arc, made in such great haste, as valueless compared with the distance as impressed upon the mind from three comparisons, and verified by observations of a reliable character since arriving at home.

Can any error, then, be ascribed to the measurements of Watson, a skilful observer, with telescope well mounted, and with appliances for measuring, and who not only did measure the position of the new planet, but that of the sun and 0 and 8 Cancri (three objects in its immediate neigbourhood) as well.

Have we any right to call in question the accuracy of his circles in giving the position of the new object when they correctly gave the positions of the others?

Wherein, then, lies the discrepancy, and how can it be reconciled? Again, Watson says the planet was much brighter than 6, while the stars which I saw were of equal magnitude.

Several times since my return from the eclipse expedition I have, both in darkness and in strong twilight, examined e, and I find no star near it, nor no two stars in its vicinity answering, in any particular, to those seen by me at Denver.

The above facts I submit to the world, and astronomers must deduce therefrom their own conclusions as to what the objects were. My own are reached, and, briefly stated, are as follows: -That the two objects seen by me were both intra-Mercurial planets, and that I did not-as was for a time supposed-see Cancri. Prof. Watson saw 0, and, some 42′ of arc south-east of it, another planet, and determined its position, and near to Cancri still another, whose position also he fortunately ascertained, making four in all. It will not do to say, as some have intimated, that Watson saw @ Cancri, and 42' from it a planet which I did not see, and that I, also, saw 0, and, 7' or 8' from it, another planet which he did not see. This reasoning appears to me untenable, for how could he have failed to see mine, when the diameter of his field was over 40', and had e in its centre?

If the above conclusions are true, and that four planets were discovered instead of two (as at first supposed), the question naturally arises, Which, if any one, is Lescarbault's Vulcan?

I estimated, at the time, the objects as being of the fifth mag. nitude, that is, as bright as a fifth magnitude star would appear in a clear, dark night. How much allowance ought to be made for diminution from atmospheric illumination I know not. I was then of the opinion that it would make a difference of at least one magnitude, but, having examined the region around e, and finding many stars there, and several which are quite bright, not one of which I saw during the eclipse, I think that fully two magnitudes should be allowed.

In what way can these intra-Mercurial planets (of which there are probably many) be detected?

I would suggest that, on July 29 next, a determined and systematic effort be made, with large telescopes equatorially mounted, to observe e Cancri, and, if then successful, there is hope that these planets, or some of the larger ones, may be discovered in the absence of a total eclipse, or while in transit. If

0 cannot be thus seen, then it appears to me that all time spent in their search in the sun's vicinity, except during a total or very large partial eclipse, would be time lost. Rochester, N.Y., November 8 LEWIS SWIFT

Colour-Variation in Lizards.-Corsican Herpetology IN a communication sent to you by my friend Mr. Wallace, under the title, "Remarkable Local Colour-variation in Lizards," published in NATURE, vol. xix. p. 4, mention is made of the well-known case of Lacerta (Podarcis) muralis, var. faraglionensis, only found on the Outer Faraglione of Capri, but there are many similar cases to my knowledge, and I add a note of them, for the fact, although unexplained, is one of great interest. During the last two years. while engaged in forming a complete series of the Italian vertebrate animals, I have visited and explored most of the Mediterranean islands included in the Italian sub-region, and I have invariably found that our common lizard (Podarcis muralis) constantly presents dark varieties on islets adjoining small islands: this is the case on the Scuola, near Pianosa, on the Scoglio di Mezzogiorno, off Palmarola (Ponza), on S. Stefano, off Ventotene, on the Toro, off Vacca (Sardinia), on Lisca nera, Lisca bianca, and Bottaro, off Panaria (Lipari), on Filfla, off Malta, and on Linosa, near Lampedusa. The extreme cases are those of the Faraglione off Capri and Filfla, where a nearly intense black is obtained; next comes Toro, and next Linosa; only the latter case might be explained by the " struggle for existence" theory, for the lava rocks of Linosa are black; but such is certainly not the case with the other islets, and, pace Dr. Eimer, the Faraglione is gray, while Filfla-on which I spent a pleasant day in October last-is painfully white in the glaring Maltese sun, so that its black lizards are most conspicuous. I may add that few creatures I know vary more in colour than Podarcis muralis, even in the same locality; two most distinct varieties occur promis. cuously on the small flat islet Formica di Grosseto.

Going over my Mediterranean herpetological notes reminds me of an interesting discovery I made last summer in Corsica, an island of great interest, which, strange to say, is rarely trodden by naturalists. Most of your zoological readers will be aware that, in 1839, Prof. Savi, of Pisa, described two new species of Italian Urodela, both from Corsica, viz., Salamandra corsica and Megapterna montana. The former has been quite neglected by modern herpetologists, or else placed among the synonyma of S. maculosa, simply because no one had Corsican specimens to compare. Now it is evidently nearly allied to the Continental form, but quite distinct, as the specimens I collected testify, all of them presenting the distinctive characters pointed out by Savi forty years ago. A nearly similar lot befell Megapterna montana, which Savi described nearly contemporaneously with Genè's description of Euproctus Rusconii, from Sardinia. Buonaparte, in his "Fauna Italica," united the two under the name of Euproctus platycephalus, given by Gravenhorst in 1829 to a newt, sine patria, preserved in the Breslau Museum; and most naturalists have followed Buonaparte, especially later writers on the subject, as Strauch, De Betta, and Schreiber, whilst others, acting more wisely, stuck to Genè's name. I believe that since Savi's day no one has studied the Corsican form, whose essential characters pointed out by the Pisan naturalist, who had only two specimens to work on, were overlooked even by his contemporary, the Prince of Canino; this explains all. Last year I rambled and collected all over Corsica, and found Savi's newt quite common in all the mountainous districts; I secured about 150 specimens of both sexes and all ages, even larvæ, and on my return to Florence was much surprised to find them quite distinct from the Sardinian Euproctus I possess; this made me refer to the original descriptions, and thus I found that Savi and Gené had described two very distinct species, and described them well. The two Italian species of Euproctus may be thus

defined:

E. Rusconii, Genè: Parotids wanting. Skin smooth, with small whitish tubercles scattered, especially about the sides of the head and neck. Female with a small conical pointed fibular tubercle, very like a rudimentary finger. Hind fingers slender and cylindrical. Irregular dark blotches on the throat. Size somewhat larger than the succeeding species. Hab. Sardinia.

E. montanus, Savi: Parotids small but distinct. Skin rough and granular. Female with a large, obtuse, compressed fibular tubercle, more like a ridge or crest, than anything else. Hind fingers stout, broad, and flattened. Throat uniform, rusty,

without blotches; often a red or yellow dorsal stripe. Hab. Corsica.

As to Euproctus platycephalus, Gravenh., only a careful examination of the type-specimens, if yet existing in the Breslau Museum, can settle to which form it ought to be referred, but if their locality is unknown, I believe it better to suppress the name. Euproctus platycephalus is said to be found in Spain, but as I have no Spanish specimens, I cannot give any opinion on that form. In conclusion, I may add that Buonaparte was perfectly right in separating from the former the North African species T. Poireti, which is very distinct from our Italian Euproctus, in the shape of the head and body, and in the complete absence of any fibular tubercle in the female; it ought to be called Glossoliga Poireti. HENRY HILLYER GIGLIOLI

Florence, November 16

Commercial Crises and Sun-Spots

"Com

REFERRING to Prof. Stanley Jevons's article upon mercial Crises and Sun-spots" in NATURE, vol. xix. p. 33, I beg to draw your attention to the inclosed circular which I issued to my subscribers in April last.

The figures relating to the "Failures in England and Wales," were compiled by my clerks, under my own direction; those relating to the failures in the United States and Canada were supplied by Messrs. R. G. Dun and Co., of New York and London, and it may be observed how nearly they agree (ie., the failures in England and Wales, and those in the United States and Canada) in their fluctuations, and that there is an agreement between both sets of figures and the sun-spot period.

I have not been able to obtain similar figures for continental states, but I have observed that the complaints of depression in trade there agree, in substance and in time, with those in this country and North America. I have also noticed similar complaints from the southern hemisphere, especially New Zealand.

I refer to Dr. Hunter's suggestion of an Indian famine period in my circular, but I do not find that the famine period in India agrees, in point of time, with the depressions in the temperate zones; it is very probable that the excess of sunshine which produces drought and famine in India has an opposite effect on the prosperity of England and all other countries lying between the same isothermal lines, and that the more moderate degree of sunshine which may suit the Indian cultivator is insufficient to properly ripen English wheat and other produce (oats excepted).

Since April last I have taken several opportunities of ascer taining from agriculturists the effect of the variations in the sunspots upon their yield of wheat, &c., and I find an agreement between them that during these years of minimum sun-spots the yield has proved bad when thrashed out, in consequence of the kernels being much smaller than in other years. I do not know whether the test has ever been tried or not; if not, I would suggest that some scientific observer should weigh an ounce, or a few ounces, of the kernels of each kind of grain grown in England every year, and count the number of them. I think it would be found that in years of maximum sun-spots wheat and barley kernels weigh their heaviest and oats their lightest, and that these proportions would be reversed in the years of minimum sun-spots. The difference in each kernel or in an ounce of them may, taken alone, appear trifling; but if it is an indication of the difference in the yield of the harvest throughout the whole kingdom, may be a fact of the greatest importance as showing the cause of the cyclical variations in the prosperity of the country, and it may be of great value to land-owners and agriculturists generally as a guide in the rotation of crops and in allowing fields to lie fallow.

it

It is in this direction that I look for the causes of commercial

depression. The whole of our "home" trade is dependent upon internal prosperity, and likewise a large proportion of our "foreign" trade. Other causes may have some effect upon either or both, such as peace or war, trade-unionism, bankmanagement, and the like; but the influence of the sun is too far-reaching and too powerful to be checked thereby. Man, by studying the working of its influence and power upon his daily life, may learn how to guard against much of the distress which periodically recurs. JOHN KEMP

Aspley Guise, November 16

"London, April, 1878

"Failures in England and Wales "We append a Summary of the failures in England and

1873 2,354

...

...

1874 2,193 1875 2,331

2,744,

1876 1877 2,829

...

...

...

...

...

...

...

...

4,081 4,131

...

3,555 4, 139

...

3,997 1,589

2, 191 1,980 2,299 2,428

...

...

...

4th quarter.

4,233
3,501
5,207
1,985

1,837 I,994

1,795 2,054 2,339

...

...

...

...

Strange Properties of Matter

J. K.

"The question occurs: Does the number of failures in a year de pend upon natural causes? that is to say, Would the number rise and fall periodically according to the state of trade (or national prosperity) if the Bankruptcy Law remained constant? Whenever failures have become frequent, complaints have been made against the Law, and not without reason, but many who com. plain ignore the existence of any other cause. We compared the foregoing figures with the scientific tables recently published in NATURE, from the pen of Prof. Balfour Stewart, and, being struck with the coincidence in their fluctuations, we further compared them with the statistics published by Messrs. Dun and Co., of New York, of the failures in the United States during the past eight years, which period, being that of the existence of our present Bankruptcy Law, affords us a fair opportunity for making a comparison. Messrs. Dun and Co. report the following as the total failures in the United States during this period:1870, Number of Failures, 3,551

1877, "Evidently the same causes which were at work in England to depress trade and overwhelm the struggling and improvident classes, were equally effective in other countries-similar complaints of depression come to us from every part of the globe.

"The discussion which has arisen out of Dr. Hunter's sugges. tion of a 'famine period' in India, has brought to the public some knowledge of the existence of natural periods or cycles, of an average duration of 11'9 years each. The suggestion that England is affected with the same regularity is but reasonable, and although fortunately for us as a nation the effects do not produce famine, it appears evident that some degree of suffering is caused, and that the number of failures is thereby materially increased the commercial panics which have occurred with about the same regularity furnish further evidence that this is the case.

"If we make due allowance for the excessive number in the last quarter of 1869, caused by the change in the Law, we find that the maximum number of failures in the last cycle occurred in the year 1868, which was the year succeeding the natural minimum; hence we may conclude that about a year is required for the full effect of the natural depression to be reproduced in commerce. The twelve months from October 1, 1867, to Sep; tember 30, 1868, appear to have been more serious to commercial men than either of the complete years, according to the number of failures :

"In the 4th Quarter of 1867 there were 4,233 failures.

I wrote to Sir W. Thomson, F.R.S., giving him a description of the above experiment, and in return I received a reply asking me to come and show him the experiment at his laboratory. I accordingly went up to the Glasgow University, and repeated it before him. He was very much interested, and advised me to write to NATURE, giving a description of the experiments. Sir W. Thomson gave the following explanation-That it was a remarkable case of "cohesion," the two metals, in fact, "welding," although the temperature was far below the melting-point of silver. The above experiment can be performed successfully at lower temperatures than 500° C., if smaller pieces of foil are taken. Other metals, for instance, copper and aluminium, cohere to silver in the same manner as platinum, but less strikingly.

Experiment No. 2.-A Curious Resonator

Some months ago I made the following experiment :-I took a small tuning-fork and struck it on the table. After the note had died away, so that it was no longer audible, I held the fork in the tip of the flame of a Bunsen burner, when the note was given out, so that it could be heard at some distance. I showed Sir W. Thomson this experiment, who gave the following explanation-That owing to the difference in density of the gases in the flame, the flame acted as a resonator, and so the note was emitted.

It seems to me that experiment No. I could be made the subject of an interesting research, but as I am wholly engaged in commercial pursuits, I am unable to take it up.

Glasgow, November 12

CHARLES A. FAWSITT

Galvanometer for Strong Currents

communication, in NATURE, vol. xix. p. 33, that the galvanoI MUST confess that I was surprised by Mr. R. E. Baynes' meter I have proposed in NATURE, vol. xviii. p. 707, has already been described. Before writing my article I have searched a good many books and journals relating to the subject without finding an allusion to any such instrument. Since Mr. Baynes drew my attention to "The Elements of Physical Manipulation," by Prof. Pickering, of the Massachusetts Institute of Technology, U.S., I have procured this book and find that it certainly does contain the theory of a galvanometer like mine, with the coil moving round a horizontal axis. As far as I know, such an instrument has, however, not been practically employed either in this country or on the Continent before I introduced it, though its want must have been much felt for some time past. This seems to show that Prof. Pickering's description of the instrument has not been brought to the general