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quarter of an inch long. The thorax is of a drab or greyish-brown colour, with a fairly well-defined stripe of a slightly darker shade centrally situated. The dorsal portion of the abdomen is slate, or lead colour; the ventral, a trifle lighter. Each segment of the abdomen bears two spots of a darker hue, but which disappear on looking at the creature with the head pointing towards the observer. The thorax and abdomen are fairly clad with tolerably short hairs, the legs are of the same colour as the abdomen, the eyes a chocolate brown. The proboscis, for about half its length, is fleshy; the remaining portion, towards the extremity, being considerably harder, but scarcely chitinous. When dealt with microscopically, it will be found that the lobes of the labium, although small, are capable of being expanded, and then

impression that a minute molar is being observed. These are all rather dark in colour, and, for the size of the creature, very strong.

A modification of the basal portions of the pseudotrachea form the secondary and third sets of teeth. The bases spring from different parts, and become united as they approach the free end. They are very thin and delicate in structure. On comparing this example with preceding illustrations, it will be found to be by far the most minute yet dealt with, yet a comparatively powerful set of organs are presented; in fact, it would appear that the size of a fly has practically little to do with the general arrangement beyond limiting the size of these organs, but that the nature of the food has probably a much closer bearing on the subject.

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reveal a rather interesting set of organs of dentition. These consist of primary, secondary, and third sets of teeth in some portions of the mouth. Viewing them in a lateral position, the primary set are six in number, the two marginal members being of the same type as the blow-fly; then follow on one side (which in its natural position is the fore part of the mouth), two teeth somewhat similar, yet presenting a slight change in form, inasmuch as one of the two points which terminate the organ is considerably longer than the other. One tooth of this form also succeeds the lateral one at the back of the mouth, but it will be observed the long point is here reversed. The remaining tooth of the primary set is rather remarkable, as it bears three points, and, when looked at with an eighth of an inch power, conveys the

I

PRESERVATION OF THE

EYESIGHT.

OBSERVE with great pleasure

that one of the Christmas Annuals has been printed on green paper with the type in blue ink, with the praiseworthy intention of saving the eyesight of readers.

The subscribers to SCIENCE-GOSSIP probably use their eyes more diligently than most persons, both in reading, drawing, working with the microscope, and examining minute objects; this is a question therefore that interests them nearly.

I think it well to point out that, while the book printed as I have described may be better than similar works printed upon dead white paper, the colours of both the paper and the type might be greatly improved. The paper is too much of a bluish-green, and the ink is too bright a blue. Were the paper more of a yellowish-green, and the type dark olive-green, the result would be much more restful to the eyes. I find it is a great benefit to read this book through glasses of a smoky brown tint; the letters appear a less vivid blue and are much sharper defined. Furthermore, a great benefit might be gained by using heavier type, that is, not larger letters, but letters with the fine strokes thicker than they are usually made.

I believe the publishers of SCIENCE-GOSSIP have already paid some attention to this question, and I trust it will one day bring forth fruit.

JOHN BROWNING.

WE have received a series of six slides from Mr. H. Vial, Crediton, containing admirable anatomical sections, beautifully mounted.

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GOSSIP ON CURRENT TOPICS.

By W. MATTIEU WILLIAMS, F.R.A.S., F.C.S.

IN

N the October number of "The Popular Science Monthly" is an interesting account of "the trading rat," alias "mountain rat," "timber rat," and trade rat." His place of residence is the Rocky Mountains and adjacent hills. He is larger than our domestic rat, his tail not rat-like, but more like a squirrel's, only less bushy, being covered with fur. Cats are afraid of him, and when unacquainted with human habits he is not afraid of men. The commercial reputation and name of these animals is founded on a curious habit. They help themselves to stores of food, but scrupulously pay by means of barter for all they take. Examples of this are given in detail. The contents of a bread-pan were annexed, none of the bread left, but it was equitably refilled with scraps of leather, chips, bones, mouldy beans, rags, &c. The bread thus abstracted was found carefully stored and hidden in an old tin can, together with bacon rinds, bones, rags, &c. In another case a meal-box was deprived of a portion of its normal contents, and the remainder was mixed with bird-shot. The crown of a new hat was eaten round, and by way of compensation the hat-box was filled with rags, remains of food, wheat and dried fruits. Knives, spoons, watches, and other glittering things appeal to their acquisitiveness, and are accordingly abstracted and hidden away, miscellaneous "dry goods" being substituted for the hardware. Red cloth is similarly attractive, especially as nest-building material. Their remarkable intelligence and natural gentleness suggest the possibility of domestication, and training them to useful industry.

Windmills appear to be looking up. According to Mr. Alfred R. Wolfe, who has published in New York a treatise on "The Windmill as a Prime Mover," their use is increasing, it is now greater than at any other period in the history of the world. We are so accustomed here to regard them as antiquated and superseded by steam-engines, that this statement will be doubtfully received by many. Mr. Wolff states that in some cities of the United States, on an average, over five thousand windmills are manufactured annually. They are chiefly used for domestic purposes, such as pumping and storing water in isolated country houses. We are also informed that great improvements have been made, that the American patterns are superior to those of Europe. This should be the case, as our European engineers (excepting Dutchmen) have scarcely condescended to look at such old-world contrivances during the age of steam. Modern science must surely be able to contribute something in this direction.

The motion of the wind is the most economical and generally distributed source of power available by man, and certainly should not be neglected. The

principal objection to it, its variability, may now be overcome by the use of compressed air and electrical accumulators. At our present rate of coal wasting a scarcity of that source of power in this country is within easily measurable distance, and it is well to know that a substitute exists, one which, if but partially utilised, might supply us with a vastly greater amount of horse-power than all our steam engines ten times told.

The testimony of Mr. Mitchell Henry concerning the merits of the Caucasian variety of the prickly comfrey (Symphytum asperrimum) is of great value. Having visited him at Kylemore Castle, and seen what he has done there in converting great areas of the most obstinate of Irish bog wastes into luxuriant meadows and arable land, and the mountain slopes of the Connemara desert into lovely gardens and most luxuriant shrubbery, with choice and tender exotics flourishing where gloomy chatterers and indolent landlords tell us that ordinary timber cannot thrive on account of the wind-I read the letter in the "Times" with much interest and perfect faith in its practical reliability. Instead of making an abstract of it here as at first intended, I enclose it to the editor to reprint in full, as I cannot condense the plain statement of facts without omitting useful information. The agricultural transformations in the neighbourhood of Kylemore Castle present the most interesting and hopeful sight I beheld during three summers' wandering through Ireland. If every Irish landlord did his duty as Mr. Henry has done, Irish misery would be at an end, and the demand for Irish labour on Irish soil would effect a considerable reemigration of true Irishmen from America.

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"A PAYING Crop.
"To the Editor of the Times.'

Sir, I have occasionally sent you notes from this place on agricultural matters, and it may now be useful to the farming interest to receive a confirmation of the great value of a crop introduced of late years into the United Kingdom as a forage crop, inasmuch as conflicting statements have been made about it. I refer to the Caucasian variety of the prickly comfrey (Symphytum asperrimum).

"Five years ago I obtained a small supply of the roots from a London agent, and planted them in a light sandy soil in which they did not do very well. The roots were then taken up, divided like Jerusalem artichokes, and transplanted into reclaimed peat land, receiving a good supply of farmyard manure. Here the prickly comfrey has flourished amazingly, and by subdivision now covers several acres. It has been cut this year already five times, and will be cut again before Christmas, yielding by careful weighing after the present fifth cutting a total of 40 tons to the acre.

"The plant is uncommonly handsome, and when planted should have intervals for its growth of not less than two feet, and when gathered it should be

cut down even with the ground and receive a dose of liquid or other manure. Cattle eat it greedily, and it is excellent for dairy cows as it does not flavour the milk. I have seen it stated that the roughness of the leaves makes it distasteful to cattle, but this is an error. It is an invaluable food for pheasants, ducks, and all kinds of fowl, and if chopped up for them in that most useful instrument, Starritt's American circular cutter, and mixed with barley meal or crushed Indian corn, it fattens them rapidly, and saves a third of the grain. I have had two of these mincing machines, one large and the other small, both purchased from Gilbertson & Page, Hertford.

"Like all broad-leaved plants, which derive much of their food from the air and the rain, comfrey grows best wherever swedes and mangolds flourish, and amply repays the expenditure of a fair supply of manure. It has been stated that no manure is wanted, but this, as regards all plants, is nonsense, for in some way or other you must restore to the soil what you have taken out of it, and root crops especially exhaust the soil. Preserved as ensilage prickly comfrey does not seem to have done very well, and the product is unusually disagreeable in smell.

"It may be added that the common English comfrey used to be employed as a poultice or to stop bleeding, for it contains much mucilage. "I am, Sir, faithfully yours,

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Dr. Fiordispini, Director of the Manicomio, the great lunatic asylum of Rome, tells us that among a staff of 327 persons in that establishment who are engaged in watching and attending the insane 3'98 per cent. have themselves become insane. This amounts to I in 25 persons, while of the entire population of Rome the proportion is only 1 in 585; or otherwise stated, the attendants at the asylum are 23 times more liable to insanity than people outside. Dr. Fiordispini connects this with the tendency to imitation, or moral infection. The history of mankind in all countries plainly demonstrates that moral epidemics have prevailed either by imitation or some influence that is very imperfectly understood. The facts stated by Dr. Fiordispini plainly teach, that no persons having even the remotest hereditary tendency to insanity should seek employment in a lunatic asylum.

The Japanese are doing good service to science and to themselves by the systematic study of earthquake movements, and the British Association is co-operating with them. By suitable instruments, seismographs, the movements of the earth are made to describe themselves, to draw their own portraits on suitable paper. These diagrams tell a great deal, and to render them more expressive, artificial earthquakes have been made by exploding dynamite in the ground, dropping cannon-balls from various

heights, and otherwise shaking the earth in a definite manner, so as to compare the seismograph diagram of an artificial disturbance of known character with the natural disturbance, and thus lead on to explanations of the natural phenomena. Last year eighty natural earthquakes were specially studied by the British Association Committee, the year before thirtynine, and the year preceding that twenty-six. The Japanese have seismographs in their coal-mines as well as above ground. The results are very interesting, but too elaborate for me to attempt anything like a general account of them here, beyond describing a very practical application of these researches, viz., the determination of how to construct a house which shall resist earthquake motion.

This has been done by resting the foundation on cast-iron balls. At first 10-inch shells were used. The record of a seismograph placed inside a house thus constructed showed that although it was subjected to considerable movement at the time of an earthquake, all sudden motion had been destroyed. The winds and other causes produced much more serious movements than the earthquake. The house was floating too freely. Then 8-inch balls were tried, then 1-inch, and finally the house was rested at each of its piers on a handful of cast-iron shot of only

inch in diameter; these shot rest between cast-iron plates. The friction in this case was sufficient to resist the disturbing agency of the wind, while the earthquake movements, communicated of course to the piers, merely rolled the shot under the foundation of the house without moving the house itself. I should add that the houses were not of the London suburban jerry order of architecture, not with 9-inch walls made of rotten bricks set in mortar made of dusthole ashes, but were respectable wooden and iron structures. As I have said before, we shall some day take our turn in the matter of earthquakes, and when we do the excessive population of suburban London will be very much regulated, and "the entranchisements of leaseholds" will be radically affected.

Mr. A. Buchan's paper read to the British Association on the Rainfall of the British Islands from 1860 to 1883 is very interesting. One of the most striking facts brought forth is the quantity of rain that falls in Glencoe, viz., 128 inches. This is the heaviest in Scotland. The average in the regions of heaviest rainfall, viz., Skye, and a large portion of the mainland as far as Luys, on Loch Lomond, the greater part of the Lake District, a long strip including the more mountainous part of North Wales, and the mountainous district to the south-east of Wales, is 80 inches. The smallest rainfall is in the south-east of England. The observations were made at 1080 stations in England and Wales, 547 in Scotland, and 213 in Ireland.

Weather prophets are usually very unfortunate; their failures are generally proportionate to their

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