Page:Hardwicke's Science-Gossip - Volume 1.pdf/61

. 1, 1865.]

finds the first traces of man in Scotland, while the shell mounds with chipped flints he referred to the same epoch as the blown sand and beds of peat, i.e., to the most recent period during which the land was raised to its present level.

.—These are very interesting objects for the microscope, and offer a great variety of form and markings—some are smooth, others tuberculated, spiny, or with convolute ridges. The figures given are those of two climbing plants, a species of Passion-flower (Passiflora incarnata) and a Thunbergia (T. alata). These objects may be examined with great facility, and mounted, either dry or in fluid, with very little trouble.

.—I have lately mounted as a microscopic object a portion of the scale attached to the seed of the fir tree (Pinus sylvestris). The spiral vessels are shown very clearly. As I have never heard of this as a microscopic object before, I thought some of your readers would like to make it an addition to their cabinets.—W. Gibson.

.—Here is one of the most degraded of animal forms—the little Amœba—a creature to be found in pools of fresh water in the summer time, but not so easily discovered as some of our naturalists would lead us to imagine. Watch him closely! He is but an irregularly-shaped mass of jelly, and very minute; moreover, he is quite transparent, and is not (as our quack advertisements have it) "troubled with a liver," nor indeed with any organ at all. He is really, as a lady once remarked to me of a snail—"all squash;" and yet, as I said before, watch him! Lo! a minute animalcule has just brushed past him. Ah, luckless animalcule, not past! for the Amœba has thrown out a long whip-like string of jelly, in which thou art entangled. Struggles are unavailing. The relentless monster has seized his quarry; and see! already he is throwing out other arms, hydra-fashion—now two, now four. In a moment a dozen hungry arms have closed around thee. Stay! "What will he do with it?" Art thou to be kept "in durance vile," hapless infusorian? 'Tis true thy cruel tyrant hath got no Bastile in which to entomb thee; a far worse fate is being prepared. The Amœba is gradually pushing his prey into the substance of his body. This has subsequently closed over it; and what do we behold? A transparent sphere enclosing the unfortunate animalcule, who is now subserving the comfort of the oppressor by undergoing rapid digestion. After some time, when all the nutritious materials have been abstracted, the remnants are quite unconcernedly forced out through some portion of the gelatinous film.—Lawson's Popular Physiology.

.—Messrs. Powell & Lealand have completed an object glass of 1-50th of an inch focus. It was exhibited at the October meeting of the Microscopical Society, at King's College. The object shown was a Podura scale, power 4,000 linear, perfectly free from chromatic and spherical aberration, the definition and penetration excellent. It was thought a wonder when this firm produced a 1-16th, still greater when their 1-25th made its appearance, but now they have reached a 1-50th, the greatest wonder of all.

.—T. K.'s Paper on the size of objects as seen nearer or farther off by the eye is not quite satisfactory, as he proves the fact, but does not show how it is. The reason is, that as an object approaches the eye it is seen under a larger angle. Thus, if at 10 inches from the eye an object is seen at an angle of 50 degrees, if it be brought to 5 inches from the eye the angle is then increased to 100 degrees, which being twice 50, the object is seen apparently twice as large linear. And this is all a lens does; it enables us to see clearly an object at a greater or less angle than it can be seen distinctly by the naked eye.—E. J. S.

(Chirocephalus diaphanus).—They swim upon their back, and in fine, warm weather, when the sun is not too strong, they may be seen balancing themselves, as it were, near the surface by means of their branchial feet, which are in constant motion. On the least disturbance, however, they strike the water rapidly with their tail from right to left, and dart away like a fish, and hasten to conceal themselves by diving into the soft mud, or amongst the weeds at the bottom of the pool. It is certainly the most beautiful and elegant of all Entomostraca.—Dr. Baird's Entomostraca.

.—Take a quantity of the oldest balsam, place it in an open glass cup, pour on and mix with it as much chloroform as will make the whole quite fluid, so that a very small quantity will drop from the lip of the vessel. Having thoroughly mixed, pour the prepared balsam into long thin half-ounce phials, cork and set them aside for at least one month, now and then turning the corks to keep them loose. It sets quicker than if only mixed when wanted. I use no heat either to the balsam or the glass slide, nor, in fact, in any part of the process. Objects which have been immersed in turpentine need only be rinsed in clean turpentine, placed in position on the glass slide, a sufficient quantity of balsam dropped from the lip of the half-ounce bottle, and the cover laid on gently without delay. In a few days, or at most a week, the slides may be safely used with care; in a fortnight the balsam will be firmly set.—W. H. Heys in Microscopical Journal.

.—The following choice sentence, containing the statement of a circumstance new to botanical science, is extracted from a little work entitled "Shrines of Bucks" (p. 57):—"The blush rose, climbing with loving arms around the hawthorns and other shrubs, that form the boundary line of the fields, and the bindweed, azure-hued as the blue sky above us, mingles its bright flowers with the fragrant honeysuckle, or the thorny sweetbrier, that fills the soft summer breeze with fragrance."—B.