[A very neat way of arriving at specific gravity in its densest form is to distil the "funny column" of a weekly newspaper. To arrive at the desired result in the speediest way, let the operation be performed in what is known among bucolic journalists as a "humorous retort." Density and closeness should not be spoken of as equivalent terms. The former is a common quality of the human skull, rendering it impervious; whereas a man may be very close and yet capable of being stuck,—with bad paper, for example.]
"3. In mentioning the constituents of the atmosphere, he adopts without explanation the loose statement of some of the books, placing carburetted hydrogen on the same footing as to constancy and amount with carbonic acid, and making no allusion to nitric acid. Yet chemistry has shown, that, except in special localities, carburetted hydrogen occurs only as a slight trace, the existence of which in most cases is rather inferred than actually demonstrated, and that it has no important office to perform,—while nitric acid shares with ammonia in the grand function of the nourishment of plants. In a later paragraph the error is aggravated by the assertion, that 'no chemical combination of oxygen and nitrogen has ever been detected in the atmosphere, and it is presumed none will be,'—as if every flash of lightning did not produce a notable quantity of this compound, which, washed down by the rain, may be detected in almost every specimen of rain-water we meet. What would Johnstone, Boussingault, Liebig, and the other agricultural chemists say to this?"
[For complete proof on this head, be struck by lightning. For ourselves, we are convinced, and would rather have some other head taken for an experiment by way of illustration. But any of our readers who is unsatisfied has only to place himself in front of a lightning-express-train with an ordinary conductor. To insure being struck, let the experimenter provide himself amply with patent safety-rods. At least, this result is pretty sure in houses, and is worth trying out of doors.]
"In the same connection he characterizes nitrogen as a substance 'not condensible under fifty atmospheres,' leaving the reader to infer that the preceding ingredient on the list, oxygen, is condensible (liquefiable) within that limit of pressure, and that nitrogen becomes liquid at or above it; whereas neither oxygen nor nitrogen has ever yet been compressed into a liquid, although a force of more than fifty times fifty atmospheres has been brought to act upon them."
[We consider an experiment requiring twenty-five hundred atmospheres, when the thermometer marks 93° in the shade, indictable at common law. To desire more than one, under such circumstances, is unreasonable, and even wicked.]
"4. In referring to the Thermo-barometer as a means of measuring heights, the writer confounds the late Professor Edward Forbes with Professor James D. Forbes, recently of Edinburgh, but now Provost of the University of St. Andrews. The former was a great Zoölogist and Botanist, and did not occupy himself with investigations in Physics; the latter is an eminent Physicist, the author of the viscous theory of Glaciers; and it is he who made the observations here ascribed to the 'Professor Forbes, whose untimely death the friends of science have had so much reason to deplore.' The author adds the further mistake of supposing that the numerical constant, 549 feet for each degree, determined by James Forbes for Scotland, is equally correct for all latitudes."
[This hardly needed confutation. No university requires any numerical constant of height as qualification for a degree; and if they did, 549 feet would be excessive, unless, perhaps, at Warsaw, where everybody is tall enough to end in ski.]
"5. Our essayist discloses but an imperfect inkling of knowledge on the subject of capillarity in barometers, when he speaks of this complex action as equivalent to the attraction between the mercury and the glass tube; and he commits a yet graver mistake, practically speaking, in reiterating the long exploded error, that 'the weight of the atmosphere at the level of the sea is the same all over the world.' No fact in Meteorology is better established than that the mean pressure at the sea-level is different for different latitudes. In the vicinity of Cape Horn the barometer is three-fourths of an inch lower than at the Equator, and according to Schouw the pressure increases from the Equator up to a certain latitude (38°) in both hemispheres, and diminishes thence towards the Poles."
[The connection between capillarity and the fat of the common bear is well known to all manufacturers of trycoverus compounds, and they are probably right in advertising that grease of this description restores tone to the hair,—of course a fine beary tone. As the weight of the bear depends on his fat, the inference to a bear-ometer is obvious. It is a familiar fact that the bear supports life during hibernation by sucking his paws; but it may not be so generally known that the waste thus induced in the anterior extremities is restored by the moral consciousness of the animal that the fat he is so carefully hoarding is to confer a posthumous blessing on mankind. This is a touching example of the adaptation of means to end, and Shakspeare, the great natural philosopher, has made use of it for one of his most striking metaphors, where he says, "that the thought of something after death must give us paws.">[
"6. Discoursing on the elasticity of the air, the writer styles it 'the most compressible of bodies,'—as if it had any advantage in this respect over the numerous other species of gaseous matter. As to the illustration which he gives, namely, that 'a glass vessel full of air, placed under a receiver and then exhausted by the air-pump, will burst into atoms,' we can only say, what every schoolboy knows, that the bursting would be inwards, unless, indeed, our meteorologist means that the external receiver was to be exhausted, and in that case he should so have expressed himself."