€t)c ^0}>ular Science ^ttos 



AND 



BOSTON JOURNAL OF CHEMISTRY. 



Volume XXIII. 



BOSTON, DECEMBER, 1889. 



Number 12. 



CONTENTS. 



Familiar Science. — News From the NebuljE 175 



A Monster Kaleidoscope 176 



With a Scientific Gathering 177 



Pre-Historic Man 178 



Practical Chemistry and the Arts. — An 



Interesting Chemical Family 179 



The Expansion of Wrought-Iron . . . . 179 

 The Scientific Knowledge of the Ancient 



Greeks and Romans 180 



Industrial Memoranda 180 



Home, Farm, and Garden. — The Production 



of Champagne in France 181 



The Horse-Shoe Pelargonium 181 



A Lofty Garden 182 



Gleanings 182 



Editorial. — Phosphorescence 184 



Indian Jewelry 184 



Paris Letter 185 



Meteorology for October, 1889 185 



Astronomical Phenomena for December, 



1889 186 



Literary Notes i86 



Medicine and PiiARMACY.^Tuberculosis . 187 



Injuries to the Eye from Lime and Chemicals 188 



Monthly Summary of Medical Progress . . 189 



Medicinal Plants 190 



A Variegated Show-Bottle 190 



Humors 190 



Publishers' Column 190 



Eanjiliar Scieijce. 



[Original in The Popular Science News.] 



NEWS FROM THE NEBULA.* 



BY PROFESSOR C. A. YOUNG. 



On looking over an article on the nebuliE 

 which I wrote for the Boston Journal of 

 Chemistry in 1873, I find nothing to change, 

 although there is now something to add. In 

 the first place, several hundred new nebulas 

 have been discovered within the sixteen years, 

 so that the total number known is at present 

 well above 8,000. The new ones are, of 

 course, for the most part, extremely faint, 

 and some of the most interesting of them are 

 quite invisible, even in the largest telescopes, 

 — /. e., the eye cannot detect them : but they 

 impress themselves upon the photographic 

 plate, and so come to our knowledge. For 

 instance, within a small area of about ten 

 square degrees, in and near the constellation 

 of Orion, Professor Pickering has found upon 



»Thc engraving illustrating this article is furnished through 

 the courtesy of Messrs. Ginn & Co., Boston, the publishers of 

 Professor Young's Elements of Astronomy, a text-book for 

 high schools. 



his star-plates twelve new nebulae, where 

 eighteen were catalogued before ; and in the 

 cluster of the Pleiades, where a single faint 

 nebula was known in 1873, the photographs 

 show wisps of nebula attached to nearly all 

 the larger stars, with a considerable number 

 of smaller nebula; that are isolated. 



When one looks through a telescope, very 

 little is gained by prolonging the gaze, but 

 upon the 'photographic plate the action of 

 light acc'-.mulates with the time. By merely 

 lengthening the exposure (in some cases for 

 several hours) an eight-inch glass can be 

 made to bring out objects which the eye can- 

 not reach even with an eighteen-inch instru- 

 ment. 



■^ The gain from photography is by no 

 means only, or even chiefly, in the number of 

 new objects ; still more important are the new 

 features which the photograph reveals in cer- 

 tain familiar objects which, after long study 

 in the old-fashioned way, were supposed to 

 be fairly known. 



The first photograph of a nebula was made 

 by Dr. Henry Draper of New York, in Sep- 

 tember, 1880. His very first picture (of the 

 nebula of Orion) was by no means poor ; 

 but he soon surpassed it, and in March, 1882, 

 a few months before his untimely death, he 

 produced one which is not much inferior to 

 the best we now have. W'ithin the last two 

 or three years, Common and Roberts in Eng- 

 land, and Von Gothard in Hungary, have 

 specially distinguished themselves in this line 

 of work. The photographs of the nebula of 

 Orion which Mr. Common has already made 

 with his three-foot reflector, are simply mag- 

 nificent, and it is to be expected that with his 

 new five-foot instrument, now just beginning 

 its serious work, still more remarkable results 

 will be attained. 



Mr. Roberts' photograph of the nebula of 

 Andromeda is not only admirable as a picture, 

 but it has brought out certain new and most 

 interesting facts, which throw a flood of light 

 upon the structure and nature of the wonder- 

 ful object. Years ago, Mr. Bond, of Cam- 

 bridge, discovered in this nebula two narrow 

 dark streaks, or "lanes," nearly straight and 

 parallel to its length, — for the form of the 

 nebula is that of an elongated and pretty 

 regular oval, much brighter at the centre. 

 In the new photograph, these "lanes" are 

 seen to be iflerely the more conspicuous j5or- 

 tions of two narrow, oval, dark streaks, or 



channels, which entirely surround the central 

 mass, and irresistibly suggest a structure like 

 that of Saturn encircled by his rings — an 

 almost perfect exemplification of Laplace's 

 nebular hypothesis. One eminent astrono- 

 mer, indeed, has gone so far as to suggest that 

 the two small companion nebulas, which lie 

 one on each side of the main nebula and out- 

 side the lanes, are really two half-finished 

 planets. It is worth noting that the photo- 

 graph shows no trace of the "new star" 

 which in 1885 so suddenly appeared in this 

 nebula, near its nucleus, and then slowly 

 faded away. The fact that the star is not 

 visible upon the plate does not, however, 

 demonstrate its absence ; its invisibility may 

 be due simply to the fact that the region of 

 the nebula in which the star is situated is so 

 bright, that the long exposure necessary to 

 bring out the fainter details has greatly over- 

 done this portion of the plate. 



One of the most serious objections to astro- 

 nomical photography lies precisely here : the 

 retina possesses a far greater range of sensi- 

 bility than the plate. When we look at a 

 nebula, we can see at the same time its brighter 

 and its fainter regions, as well as the glittering 

 stars which here and there are scattered 

 through it. The highest beauty of the nebula 

 of Orion, for instance, lies in the contrasts 

 and gradations between the splendid stars of 

 the "trapezium," the curdled clouds of green- 

 ish light which envolope them, and the 

 impressive blackness of the "fish mouth." 

 In the best photographs of this nebula, the 

 stars are mere blotches, and the contrasted 

 darkness of the telescopic background is 

 replaced by a tangle of faint nebulous wisps, 

 which, though in themselves curious and 

 interesting, none the less obscure and befog 

 the familiar outlines. 



The photographs produced by Von Gotlrard 

 (of Hereny in Hungary), about, two years 

 ago, have excited much interest, because they 

 were made with a silver-on-glass reflector of 

 only ten inches aperture. Though the pic- 

 tures are almost microscopic in size, — only a 

 few millimetres in diameter, — they show 

 many things that before had been clearly seen 

 only with the largest telescopes ; and they not 

 only show them, but bring them out with 

 increased emphasis and clearness. The so- 

 called "whirlpool nebula" is an example. 

 The photograph does not exhibit, to be sure, 

 such a series of regular spirals, nor such a 



