Feb. 20, 1SS5.] 



]< NOV/1 .F. DC E 



147 



space \ro\ild cross the track of Urauus, if it cbanccd to 

 come in the riijht direction, with a veli>city of nearly G milts 

 per second. Uranus, then, to do what certainly l(as been 

 done if Sohiaparelli's idea is right, must have abstracted a 

 velocity of 4.\ miles per second from every one of a (light 

 of meteors travelling past it. Now it may be barely 

 possible (I doubt it it is, but the calculations nece^siry aro 

 too absti'use to be entered on save for a very special 

 purpose) for Uranus to abstract so great a velocity 

 from a body travelling 'past him. If Uranus drew a 

 body to himself from interstellar space, no other member 

 of the solar system, not even the sun, interfering, he 

 could give to the approaching body a velocity of 13^ miles 

 per second ; but he could not give anything like this velocity 

 to a body rushing along by him with sun imparted velocities, 

 and therefore exposed for a shorter time to his inlluence. 

 Moreovtr, in any passage by Uranus some part of the 

 velocity abstracted or added in one part of the pafsago 

 would bs restored or taken away again in the remaining 

 pa t. At the utmost, Uranus might abstract from a single 

 meteor some 4.\ miles per second of its velocity of 6 miles 

 p;r second. But Uranus could not possibly j reduce the 

 same etfects on the members of a flight of meteors, however 

 closely we may conceive them to be set Some would have 

 their velocities much less effectively reduced. And the 

 deflections of direction would be also altogether different. 

 Nothing could save a meteor-flight from being dispersed 

 along widely divergent paths if it came near enough to 

 Uranus to have the motion of any of its members sufii- 

 ciently affected to make them travel henceforward in such 

 an orbit as is actually pursued by the November meteors, 

 which all travel along the same path. 



This which is true cf one meteor system or comet is 

 true of all. Under no conceivable conditions cou!d a 

 meteor - flight be introduced into our solar system as 

 Schiaparelli imagined. Hence a different theory of the 

 origin of the families of comets associated with the giant 

 planets must be adopted. We must in some way admit 

 that every comet was once in the neighbourhood cf one 

 of the giant planets in the form of a closely-set flight of 

 meteors. This being s->, the natural explanation is that 

 each comet started from a planet, — by a process akin to 

 volcanic ejection, or in some such way. Now on the 

 one hand the sun docs eject bodies from his interior, in 

 mighty eruptions which have been actually watched ; and 

 the planets when in the sunlike state may w^ell be believed 

 to have done likewise ; and on the other hand there is 

 evidence to show that even our small earth once pos- 

 sessed the power of ejecting meteoric bodies from her in- 

 terior (Prof. Ball considers that some meteor flights still in 

 existence were earth-bom). 



On the whole, then, the view seems suggested that 

 comets like Encke's were ejected from the interior of the 

 planet on which they are still found to be dependent. 



THE PHILOSOPHY OF CLOTHING. 



Br W. Mattieh Williams. 

 II.— THE SKIN. 



THE engraving below repre.wnts in outline a magnified 

 section of a little bit of the skin of a human hand, 

 cut across those wavy ridges that are visible to the naked 

 eye on the fingers and inside of the palm. Three cf these 

 ridges are shown, the shaded upper part being the cuticle, and 

 below it the cutis or true skin. The convoluted tubes are 

 three of the sweat glands, the lower ])art of which lie imme- 

 diately beneath the true skin, and the tube or du;t rising 



from them passes through the true skin and cuticle, and 

 opens on the surface of the latt'.r, forming the "pores" of 

 the skill. The waved structure of that part of the duct 

 which passes through the cuticle 1 .suppose to be adapted to 

 the possible thickening of the cuticle, such as occurs when 

 rough usage demands further protection — the effect of 

 rowing on the cuticle of the hands, for example. 



The number of these glands, with their ducts, thus open- 

 ing on the surface of the human body has been variously 

 estimated, from two millions to seven millions. 



Every part of the bo^y is pro-i ided with them, but they 

 vary "rf atly in their distribution. On the palms of the 

 hand "there are about 2,800 to the square inch. They are 

 fewer than this on the sole of the foot, but next in abun- 

 dance there. Then they diminish successively on the back 

 of the hand, the forehead, the front of the neck, trunk, and 

 arms, where they are about 1,000 to the square inch ; they 

 are still fewer on the lower limb.s, and fewest of all on the 

 back, where they come down to about 400 to the square 

 inch. Two and a half millions is the usual estimate of 

 the whole number. 



I present the picture of these glands and ducts, and 

 state their numbers in order to convey to the mind of my 

 readers a more serious conception of the importance of the 

 "pores of the skin'' than is usually entertained by tkc 

 majority of those who speak of those pores. They aro not 

 merely the vacuous intervals of reticulated tissue, but the 

 specially constructed outlets of special mechanisms having 

 special functions to perform. We may safely infer that 

 the importance of the function bears some relation to the 

 elaboration of the machinery by which it is carried out. 



More minute examination displays still fuither elabora- 

 tion. Although the tube forming the coil and duct is but 

 1-300 of a inch in diameter, and, when all unrolled, is but 

 a quarter of an inch long, it consists of an outer vascular 

 cnat continuous in structure with the cutis, and an inner 

 epithelial or membranous coat continuous with the cuticle. 



Physiological research confirms the inference suggested 

 by the anatomical structure of these organs. They do 

 much important work. They draw from the blood which 

 circulates through the minute blood-vessels around them a 

 sour, watery fluid, containing about U per cent, of solid 

 siline matter, urea, lactic acid, and other products of 

 bodily waste ; matter which, if left in the blood, would act 

 as poison, and does so act when imperfectly removed, produc- 

 ing those general bodily disturbances with which we are too 

 familiar as the results of " taking cold," i o , checking the 

 functions of this sudoriparous machinery. 



The importance of the excretory functions of the skin is 

 strikingly shown by an experiment made by Valentin. In 

 the month of September, when thirty-thiee jears of age. 



