OBSERVATIONS OF THE SUN.
As much interest is manifested for increased knowledge of solar characteristics, and as many astronomers and numerous amateurs are daily engaged in their investigation, I have thought that the experience of thousands of observations and the final advantages of a host of experiments in combination of lenses and colored glasses, resulting highly favorably to a further elucidation of solar characteristics, would be interesting, especially to such as are engaged in that branch of inquiry.
My experiments have resulted in two important discoveries. First, by a new combination of lenses, I prevent heat from being communicated to the colored glasses, which screen the eye from the blinding effects of solar light, and thus avoid the not infrequent cracking of these glasses from excess of heat, thereby endangering the sight—whereas, by my method, the colored glasses remain as cool after an hour's observation as at the commencement, and no strain or fatigue to the eye is experienced. Secondly, the defining power of the telescope is greatly increased, so that with a good three-and-a-quarter inch acromatic object-glass, with fifty-four inches focal length (mine made by Búron, Paris), I have obtained a clearer view of the physical features of the sun than any described in astronomical works.
In a favorable state of the atmosphere, and when spots are found lying more than halfway between the sun's centre and the margin, or better still, if nearer the margin, when the spots lie more edgeways to the eye, I can see distinctly the relative thickness of the photosphere and the underlying dusky penumbra, which lie on contiguous planes of about equal thickness, like the coatings of an onion. When these spots are nearer the centre of the sun, we see more vertically into their depths, by which I frequently observe a third or cloud stratum, underlying the penumbra, and partially closing the opening, doubtless to screen the underlying globe (which, by contrast with the photosphere, is intensely black) from excessive light, or to render it more diffusive.[11] The concentric faculæ are then plainly visible, and do not appear to rise above the surface of the photosphere (as generally described), but rather as depressions in that luminous envelope, frequently breaking entirely through to the penumbra; and when this last parts, forms what are called 'spots.' The delusion in supposing the faculæ to be elevated ridges, appears to me to be owing to the occasional depth of the faculæ breaking down through the photosphere to the dusky penumbra, giving the appearance of a shadow from an elevated ridge. What is still more interesting, in a favorable state of the atmosphere, I can distinctly see over the whole surface of the sun, not occupied by large spots or by faculæ, a network of pores or minute spots in countless numbers, with dividing lines or faculæ-like depressions in the photosphere, separating each little hole, varying in size, some sufficiently large to exhibit irregularities of outline, doubtless frequently combining and forming larger spots.[12] When there are no scintillations in the air, the rim or margin of the sun appears to be a perfect circle, as defined, in outline, as if carved. By interposing an adjusted circular card, to cut off the direct rays of the sun, thus improvising an eclipse, not a stray ray of light is seen to dart in any direction from the sun, except what is reflected to the instrument, diffusively, from our atmosphere; thus proving that the corona, the coruscations or flashes of light, seen during a total or nearly total eclipse of the sun by the moon, are not rays direct from the sun, but reflections from lunar snow-clad mountains, into her highly attenuated atmosphere. Solar light, being electric, is not developed as light until reaching the atmosphere of a planet or satellite, or their more solid substance, which would explain why solar light is not diffused through space, and thus account for nocturnal darkness.
The combination of glasses which enabled me to inspect the above details may be stated briefly thus: In the place of my astronomic eyepiece, I use an elongator (obtainable of opticians) to increase the power. Into this I place my terrestrial tube, retaining only the field glasses, and using a microscopic eyepiece of seven eighths of an inch in diameter. Over this I slide a tube containing my colored glasses, one dark blue and two dark green, placed at the outer end of the sliding tube, one and a half inches from the eyeglass. The colored glasses are three quarters of an inch in diameter, and the aperture next the eye in diameter half an inch. The power which I usually employ magnifies but one hundred and fifty diameters; and I use the entire aperture of my object glass. This combination of colored glasses gives a clear dead white to the sun, the most desirable for distinct vision, as all shaded portions, such as spots, however minute, and their underlying dusky penumbra, are thus brought into strong contrasts.
AN ARMY: ITS ORGANIZATION AND MOVEMENTS.
FOURTH PAPER.
In previous papers we have briefly related the history of the art of war as now practised, stated the functions of the principal staff departments, and mentioned some of the peculiar features of the different arms of military service. It remains to describe the operations of an army in its totality—to show the methods in which its three principal classes of operations—marching, encamping, and fighting—are performed.
The first necessity for rendering an army effective is evidently military discipline, including drill, subordination, and observance of the prescribed regulations. The first is too much considered as the devotion of time and toil to the accomplishment of results based on mere arbitrary rules. The contrary is the truth. Drilling in all its forms—from the lowest to the highest—from the rules for the position of the single soldier to the manœuvres of a brigade—is only instruction in those movements which long experience has proved to be the easiest, quickest, and most available methods of enabling a soldier to discharge his duties: it is not the compulsory observance of rules unfounded on proper reasons, designed merely to give an appearance of uniformity and regularity—merely to make a handsome show on parade. Nothing so much wearies and discourages a new recruit as his drill; he cannot at first understand it, and does not see the reason for it. He exclaims: