the attention of the investigator, be he student or teacher. Why it should have been passed by as though its meaning were not worth wrestling for is incomprehensible. Since Savart wrote no light has been thrown on this singular phenomenon, for the explanation which has been afforded (presently to be quoted), cannot be called in any degree satisfactory. In the illustrations of nodal division given in various scientific works there is a puzzling contrariety hardly to be accounted for except on the supposition that our engravers are as niggardly conservative in design as the buried Egyptians, or that the engravings themselves are the cherished heirlooms of our publishers. In one work a representation of the manometrical nodal division after Koenig will be given, but carefully corrected and revised by the aid of a pair of compasses; in another a beautifully accurate copy of the original, so lopped to suit the size of the page that much mental effort and distortion of reasoning are incumbent on the reader in vain attempts to bring the engraving into harmony with the accompanying text, young eyes are mystified, it needs cold "well-worn eyes" to appreciate these fine economics of the publishing art; in another the manometrical nodal positions will be properly defined and, by some negligent inconsistency, on an opposite page an organ-pipe be depicted, admirably exact to theoretical localisation, in direct contradiction of knowledge. Faults of this kind should not be allowed to pass, they weaken faith in the teacher and are harassing to the inquirer.

Koenig in his own illustrations represents the displacement of the node as it is indicated under experiment, for this one condi tion of truth to nature had been too often before him in his manometric flames to allow of his disregarding its faithful portraiture. The difference he shows to exist as to position corre. sponds very closely with that we arrive at by other means, by calculation of scales and by the practical teachings of experimental study of the relations and arrangements of organ-pipes. Of the cause of the displacement Koenig offers no elucidation. The following explanation is quoted from Prof. Airy's treatise "Sound and Atmospheric Vibrations." In the section on open organ-pipes he says:

on

"It was found by Mr. Hopkins that the node next the open mouth of the pipe was somewhat less distant from it than that given by theory, or, which amounts to the same thing, that the place where the air has always the same density as the external air is not exactly at the pipe's mouth but somewhat exterior to it."

The extent of the disparity would be but very imperfectly com. prehended under this vague delineation. Other authors have attempted explanation, in substance the same as the above, to account for the disparity; the summary of the whole is, that science brings forward no better plea than the surmise of a pro. bable place, somewhat exterior to the mouth, which the air-wave of the lower half of the pipe has to attain before it can be properly said to be completed in length. Truly an illogical conclusion if this line of reasoning is carried out. In common fairness the upper half of the pipe may claim to be credited with a reasonable amount of wave-prolongation, seeing that at the higher orifice the internal column of air pulsates the atmosphere with far greater vigour than at the mouth, and consequently that for a similar attainment of density the due addition of wave-length would only serve to increase the disparity in relation to the half below the node.

A displacement of some sort thus receives acknowledgment although as yet the variability of the node is unsuspected.

An ap

The actual extent of the disparity between the unequal halves" can be ascertained. It is subject to laws of relation of as definite a character as are found in other dynamical problems when the elements of calculation are delicately defined. proximate estimate will be sufficient for the present purpose. For avoidance of the inconvenient "unequal halves" it will be permitted me to coin two simple terms as more distinctively representative, and to speak of them as super-nodal and sub-nodal.

If a standard open diapason pipe be made for some designed pitch, whatever that pitch may be, it may safely be predicted that the pipe will stand considerably short of the full theoretical length; æsthetically judged for musical quality, it ought to be about one-eighth less, a difference much affecting the veracity of scientific argument.

Doubtless it would be somewhat a novelty for a scientific lecturer to tell his audience that one-eighth of the whole wave. length was lost by conversion into organ-pipe vibrations, yet, unless he innocently accepts the ironical reply of Galileo on the pump question, that "perhaps Nature is indifferent to a few

feet," he is strictly in this dilemma: if the pipe is a natural standard of wave-length, the velocity of sound in air computed on the basis of the pipe's length falls very far short indeed of the philosophical estimate, 1, 125 feet per second; on this ruling the latter should be pronounced to be irreconcileably wrong, or else the frank admission made that there is no "necessity of relation" that the wave-length in an organ-pipe, giving a defined pitch, and the wave-length in the free air corresponding to that note should be identical.

Taking the several classes of pipes, from the Diapason to the Vox Angelica, ranging from the pipes of the most vigorous to those of the softest intonation, the amount of difference from full measure varies from one-eighth to one-twelfth less than that which theory demands. The loss is mainly due to the cause which enforces nodal displacement.

Our immediate inquiry is, what is the extent of displacement of the node, and what its variability? Divide the length of the already reduced pipe into seven equal parts, and the unequal halves will be in the ratio of 4 to 3. Four parts belonging to the super-nodal half, and three parts to the sub-nodal half, subject to a relative variability, according to the position of the pipe in the range of octaves, and subject to a fluctuating variability determined by force of wind, diameter of pipe, character of scale, relative size of mouth, mode of voicing, and other details, changing the proportion, perhaps, to 6:5, or even to 7:6. Whatever the extent of the variability, change in result rigidly follows change in details, with a calculable value. When, instead of the fundamental note, the pipe vibrates in harmonic nodal divisions, the lowest half-segment takes upon itself almost the whole difference, and not merely a proportional share in comparison with its segmental relation to the whole pipe. A remarkable fact, but one fully accounted for in that which I have termed the aero-plastic reed theory (NATURE, vol. viii. p. 25) for it is easy to me visibly to demonstrate that the harmonic-independent and the harmonic-concomitant are originated in the pipe by totally different natural processes.

The nodal difference detected by Mr. W. Hopkins was much smaller in extent, but there is an important distinction not to be overlooked his experiments (recorded in the Transactions of the Cambridge Philosophical Society, vol. 5) were not made with organ-pipes, but with glass tubes supported in position over a glass plate, the plate being set in vibration by friction. He expressly rejected organ-pipes by reason of their intractibility and of the difficulty of obtaining results from them of the nature desired.

In like manner we continually find experimentalists rejecting organ-pipes as insubordinate pupils; they prefer dumb pipes and the aruficial speech by tuning-forks, and having obtained such negative evidence, make a clean transfer of their conclusions to all argumentative reasonings and expositions of the nature and functions of the original, living, speaking organ-pipes. The Hon. M. Strutt, in his paper on the Theory of Resonance, printed in Phil. Trans. Nov. 1870, says :-

"Independently of these difficulties, the theory of pipes or other resonators made to speak by a stream of air directed against a sharp edge is not sufficiently understood to make this method of investigation satisfactory. For this reason I have entirely abandoned this method of causing the resonators to speak in my experiments, and have relied on other indications to fix the pitch.'

Prof. Airy is as evidently dissatisfied with the state of theory and experiment, using such phrases as these: "the matter, however, demands more complete explanation;" "that obscure subject, the production of musical vibrations in a pipe by a simple blast of air;" "possibly when the mathematical calculus is farther advanced, this may be shown," &c. Beyond the province of mathematical analysis his survey is keen, and with foresight of the results of possible experiments.

At the present date our best authorities are in effect repeating the assertion of Biot that "the particular properties of the vibrations of confined air in tubes are not yet sufficiently explained." The disturbing influence of some unknown agency may be discerned in Dulong's experiments of filling organ-pipes with various gases, and estimating the velocity of sound in these gases by the pitch produced. Similar experiments on this method are referred to by Herschel, and he, noticing how the results gave for hydrogen gas a velocity differing by one-fourth from that which theoretically had been calculated, could only account for it by supposing an impurity in the gas used for the experiments. There is little need to resort to the supposition of

an impurity; it is quite sufficient to know that an agreement in length of organ-pipe and aerial wave-length was assumed which does not exist, and that, moreover, the mechanical nature of the organ-pipe, and its delicate apparatus so wonderfully balanced for the attainment of its ends, had escaped observation. The admirable method of experiment for ascertaining the velocity of sound in gases, devised by M. Kundt, by means of glass tubes and lycopodium seed, is free from the same source of error; and, as might be anticipated, comparison shows a marked difference in estimates. In respect of carbonic acid gas and hydrogen gas, for instance, Dulong differs from Kundt, his estimate in the one case being less by one-fifth of the whole, and the other more by one-fourth; the divergence interprets itself, indicating the relation of their densities to the compelling force, the unseen mechanical action at the mouth of the organ-pipe. This will be clear when the "air-moulded reed" is fully understood in its nature and functions. When the magnetism of the earth is perceived, the dip of the needle to the north or south of the equator in accord with its localisation is explained.

The confession of "obscurity" amounts to a concession that the old theory has been found wanting, that it is inadequate to deal with facts. Whether in dealing with the larger questions here brought into discussion, or with the simpler class, the mere modifications of structure, it is equally incapable. If, for instance, a stopped pipe is pierced through the stopper and a short open pipe inserted, say a third or fourth the diameter and a third or fourth the length, what will be the effect of this on the pitch? The old theory would reply, the added length would cause a flattening of pitch, and then will come a proviso for safety's sake, that if the change converted it into an open organ pipe then the pitch would be raised in accordance with the open length. We go to Nature for her say in the matter, and find that the pitch is raised not flattened, and that the extent is about a quarter of a tone, and that further lengthening of the smaller pipe takes back the pitch again just its quarter tone. If another stopped pipe is drilled at the back with a hole of a diameter a third or fourth of that of the pipe, but so that it shall be at a higher level than the lip or edge of the mouth, in effect shortening the air column by admission of external air at a higher point, what will be the result? On the old theory we should expect the pitch to be higher in consequence. Appealing to the ear we know that, on the contrary, it is flattened. These results cease to be anomalies when viewed under the new theory, and indeed they would be predicted with confidence as the necessary outcome of the conditions.

The proposition that in an organ-pipe there is no constant wave-length for an ascertained pitch, will no doubt be discoun tenanced as novel and revolutionary, but it is true and will have to be acknowledged. A further proposition that in an open organ-pipe there are three different velocities speeding at dif. ferent rates, concurring in every vibration, and essential to the synchronic time of its note, has a still more aggressive aspect defiant of law. Not so. It is because law-known law," does not cover the facts, is unstable in its applications, and is deficient in prevision, that there is room for new hypothesis which does not play fast and loose with nature; the utmost exactitude of length in an organ-pipe is as indispensable in this as in the older theory, but the relation is one of proportion to a system, and the least and every variation will make imperative suitable or corresponding modifications in other portions of the structure. Only a whistle, yet with more to marvel at for delicacy of organisation and beauty of adaptation "than is dreamt of in philosophy."

As regards "fixity of wave-length," that characteristic reappears in a new relation, and we shall find that, allowing for retardation by friction, the super-nodal half-wave of the pipe corresponds very closely with length in atmosphere.

The cause

of the displacement of the node is involved in the physical action taking place at the mouth of organ pipes, the consideration of which is reserved for a further communication.

303

THE PHOTOGRAPHIC SOCIETY AL LTHOUGH we published last week a letter from Mr. Baden Pritchard, Hon. Sec. of the Photographic Society, impugning the justice or accuracy of our strictures on that Society, our esteemed correspondent has not caused us to change our opinion.

We have now before us the Journal of the Society for the past year (a summer vacation of three months excepted), and certainly it furnishes primâ facie evidence of the most apathetic and inefficient condition which is consistent with continuous existence. The numbers contain eight pages each, the page little more than half the size of that of NATURE, and in the whole year's proceedings there are twelve pages devoted to science, half of this being a lecture by Prof. Stokes; three or four papers of considerable value on technical points of photographic interest, and much which the charity of any semi-learned society would be largely strained in giving paper and

ink to.

There is no mention of scientific or other committees, no provision for them in the laws, no reports of investigations made or to be made, no notice of scientific discovery abroad or recognition of discovery at home. Mr. Pritchard has no need to assure us that the body " does not profess to be a purely scientific one"-the scientific element in it, so far as its own record shows, is purely fortuitous.

But without demanding scientific labours from a body not "purely scientific," we do not even find evidence of common activity in the research of practical problems, and if any of its members are, as Mr. Pritchard suggests, engaged in researches on the process and nature of film best suited for transit of Venus observations, they have not had faith enough in the countenance of their Society to place their labours before it, or ask its assistance in performing them.

Since our article appeared, the revolution alluded to has taken place, and that part of the Society in favour of reform having a majority at the meeting appointed for the discussion of the question, have carried an amendment to the laws providing that henceforward the Society at large shall select its council, and that the majority of the actual council shall not have the power to select for retirement such members as it sees fit and to decide who shall replace them, as has actually been the case hitherto; it has also been decided that the presidency shall rotate. These measures were, as we learn from the photographic papers, strongly opposed by the council, and upon being carried by a majority of 30 to 23 (the council itself voting in the minority) the entire body resigned.

As the meeting at which this stroke of singular policy was made, was that for the election of the new members of council, these were enabled to assume the reins of government and prevent the, otherwise in

evitable, total dissolution of the Society. And now that the reformers have its affairs in their Own hands, it is to be hoped that it will begin a new life of efficiency, and, remembering that it owes the cause of its existence to the labours of scientific men, give its most efficient aid to those scientific researches in which it has become an important element of investigation, as well as to those of a more technical nature which have given photography so great a commercial and industrial value. And on the other hand we bespeak for it the aid and countenance of all scientific men whose researches are in any way dependent on photography, and give it, in its reformation, our best wishes for that complete success and efficiency which will make it as useful to Science as honourable to itself and its members.

NOTES FROM THE "CHALLENGER”

THE following contributions to the literature of the

Challenger Expedition appear in the Cape Monthly. The first contribution consists of a few notes from Commander Maclear, written on the day of the Challenger's departure from Simon's Bay, and will give our readers an idea of the work still before the Expedition :

On leaving Simon's Bay, if the weather permits, dredgings and temperature soundings will be taken on the Agulhas bank; then sail made for Marion Island. This and the Crozetts will be examined; the last may be occupied by the French as an observing station for the Transit of Venus. Then for Kerguelen Island. It is not likely that the weather will allow a regular series of soundings to be taken as hitherto, but some doubtless will be taken on the passage.

Kerguelen's, or Island of Desolation, will be a fertile field of exploration in every department of science, and as it is to be one of the stations for watching the Transit of Venus, special information will be collected for the use of the astronomers who will go there towards the close of next [this] year. The longitude of the island will be determined by chronometrical measurement from the Cape, and again to Melbourne, and with the great number of chronometers (16) that the Challenger has on board, the longitude should be determined very accurately.

After leaving Kerguelen, Macdonald Island will be examined, and search made for a harbour there; and then a stretch will be made to the Ice Barrier. The investigations in the neighbourhood of the ice are very important, but great care will have to be taken not to get entangled in the ice. With steam power, and the clear weather there is likely to be in February, little danger need be apprehended. If the season should be fine, some considerable time will be occupied in this region, but if not, after a short stay, sail will be made for Melbourne, which will probably be reached in the end of March. After a few days there, to obtain the rates of the chronometers, we go on to Sydney to refit and, if necessary, dock. This terminates the second stage of our voyage.

Leaving Sydney about the middle of May 1874, and carrying a line of soundings to New Zealand, we next examine the islands about the Coral Sea and Torres Straits in August 1874 New Caledonia, New Guinea, Arofura Sea, Kaepang in Timor, Java Sea, Macassar, Celebes, and reach Manilla in November. We next look up the doubtful islands of the Western Pacific; visit New Ireland, the Solomon Islands, and Pellew, and Japan will be reached in March 1875. From Japan we cross to Vancouver's, and then to Valparaiso, examining Eastern Island and Sulay group in our course. Leaving Valparaiso in the end of 1875, we go through the Straits of Magellan to Falkland Isles, Rio de Janeiro, Ascension, and England in the middle of 1876.

The other communication, of a different order, comes from a gallant Blue Jacket, who speaks for himself and

the Challengers and their labours somewhat irreverently thus:

FROM JACK SKYLIGHT TO HIS OLD SHIPMATE

A Letter without much Rhyme and with a little Reason We've crossed the Line a many times in craft both great and small, And of them 'ere fish that's thereabouts I've caught 'em nearly

all.

It aint becos I wants to boast I says as "it is so,"
But 'cos I think that wot is wot I'm just the bloke to know.
I'll first acquaint you, topmate, with the nature of my dooty,
And show you what I've larned since last we met, my beauty.
I jined this craft last winter, got rated on her ledger
A swabber, jobber, scrubber, a sounder, and a druger.

I know, old ship, when this you see you'll say I'm flyin' hi,
But it's true as Polly-Arris is above us in the sky.

At sea we sounds-no matter, Bill, if every blessed thread
Aloft or low of canvas before the wind is spread,

In it comes! And down there goes, I've really quite forgotten
How many fathoms (half-inch), Bill, until we touches bottom.
Sometimes the timmey-noggie that holds the weights don't G
And then a fog* arises as is horrible to see.

We flies in all directions, like cats on houses sportin', The luff cr.es out, the donkey shies, and makes a dreadful snortin'

They puts aboard a man-of-war with various intentions,

It aint a regular ass, Bill, but one of them inventions

To wit, it nicks the complement, and gives the honest Jacks
More time to study politics and read their Sunday tracks.
The donkey does the hauling in, which is no doubt a blessin',
For if it had to come by hand, oh! lord, 'twould be distressin'.

We've a many curious ratins, a lot of long shore tallies
For scientifick genelmen, their servants, and their valleys.
Don't yer see these learned bosses have come to search the
ocean,

But for what, old son, 'twixt you and I, I'm blow'd if I've a notion.

I've 'eard 'em talk of Artic drift and walleys under water, And specs next week to find they've nab'd old Davy and his darter.

Of course you know they've got to find the link atween the species,

Some say as there's a coon aboard as liks it all to pieces;
I cannot tell, for well you know it aint the likes o' me
That's got a chance like swells abaft the curus sight to see.
The scientifick swells, old chap, are mad on mud, and great
On getting things like what we used in Chiney for our bait.
You know them squids and stuff we tried for catching them
there conger?

Well, it's the same; but then the name is many a fathom longer.
They seems to me to make a deal and show a great surprise
At things we've seen, Bill, many times, when first they meet
their eyes.

They only having seen them home screwed up in brine or pickle.
Perhaps its 'cos the thing's alive their fancies somewhat tickle,

I've told yer how we sounded, now I'll tell yer how we druge,
And if my life's a angel's I'll leave yer for to judge.
We hangs the drege at the yard-arm to a sort o' kind of buffer--
At explernation, Bill, yer no I always was a duffer-
It aint a bad doge neither; for when its pulled it streches
And gives a kind of surge when the dredge at summat ketches;
It's like a koncertina, Bill, but where the wind is squoze,
From end to end a set of stays like Inde rubber goes:
A block is tacked at bottom and through it runs the line-
Which is the werry bane of life to this old pal of thine;
I've burnt my hands, I've spiled my close, I torn my underneath,
I bark'd my shins and nik'd my back, and loosened all my
teeth-

All through that blessed line, Bill, which, trifling as it seems,
Is wuss nor all the nightmares that ever hunts in dreams.
The care that is required for to keep that line from breakin'
If your stationed near the donkey is a awful undertakin';
The thing flies thro' your fingers, and if stationed near the drum,
Its safe to nab you somehow by a finger or a thumb ;
Then there's the pipe and others, Bill, that raise a shout, and
call

* Row.

and each shaped somewhat like a life preserver. These are the elfactory lobes," and from the swollen head of each proceed the delicate nerves of smell

2. An enormous pair of folded masses which form the great bulk of the human brain and are called the cerebral lobes or hemispheres. These are so large and preponderant in man, as to hide every other part of the human brain when that organ is viewed from above.

3 A relatively very small portion, but one easily recog

On turning to the brain of the frog from that of man it is at first sight difficult to find out the resemblances, and to determine which portions of the one answer to definite regions of the other.

Fac. -The Brain as seen when a Vertical Longitudinal Section has been made through idle. Au, arbor vitæ of the cerebellum; c, cereBram; c, corpus callosum; cg, corpora quadrigemina: f, fornix (between the fornix and the corpus callosum is the septum lucidum); m, medalla desnata; ma, corpus mammillare; on, optic nerve; pl, pineal and, piitary body; tu, pons Varolii; s, soft, or middle com

nised since it supports two conspicuous little bodies. One of these (Figs. 69, 70, 71, pl) is called the pineal gland, and projects more or less upwards; the other (Figs. 69, 70, 71, pt) projects downwards and is called the pituitary body.

4. An also very small portion relatively, is distinguished by bearing certain small prominences (Fig. 69, cq, and Fig. 70, na and te) placed behind the pineal gland, and called corpora quadrigemina.

5. A rounded mass of finely folded brain-substance, placed at the lower part of the back of the head beneath the hinder portion of the cerebral hemispheres. This is

BIG 75-Enlarged and Diagrammatic View of a Vertical Section carried through the Corpus Callosum and the parts below. ac, anterior commissure, co, corpus callosum, cbl, cerebellum; cm, corpus mammillare; formx: /m, foramen of Monro; i, infundibulum; p, locus; perforafus medius; mo, medulla oblongata; na, nates; on, optic nerve; pc, posterior commissure; pu, pons Varolii; pl, pineal gland; pt, pituitary body; s, soft, or middle commissure; si, septum lucidum; t, lamina terminalis; fe, testes; 7, velum interpositum (between it and the fornix is a space enclosed by the folding over of the cerebrum upon the roof of the third ventricle); 3. upper, and 3, lower part of third ventricle 4. fourth ventricle-between them is the iter a tertio ad quartum venIriculum.

nterse

its po

man brain the re obvious; it is later