SPECTBOSGOnC DISCO VER Y. 429 



are the distinctive features of aerolites? M. Daubree asserts, from repeated 

 experiments upon metallic surfaces with gunpowder and dynamite, he has 

 produced the same cavities as in the aerolites, and which are simply due to 

 the expansion of compressed gases. The honey-comb surface ol these mete- 

 orites is then not due, as is commonly supposed, to the scaling off by the 

 ■unequal expansion of these extra terrestrial bodies. M. Daubree has pro- 

 duced the same characteristics on iron and zinc. The pressure which our 

 atmosphere exercises on these bodies, on their arrival within its influence, 

 is very great, as they enter at a rapidity of over 60 miles a second ; hence, 

 the fragmentation of the aerolite, its successive explosions, its breaking up 

 into a shower of tiny stones, or assuming the appearance of a "swarm." As 

 these bodies have to support a pressure of 3,000 atmospheres, their incande- 

 scence is as natural as the fusion of their surfaces. 



M. Mcnier draws attention to jDulverization of manures and of soils, as 

 stimulating the action of each. Pulverizing often moderates most com- 

 pletely the properties of bodies in flavor, odor and color. Sugar, too finely 

 powdered, loses too much of its saccharine qualities, takes an odor of cara- 

 mel and a taste of starch. The more carbon is finely divided, the more it is 

 eflScaceous as a dcoderizcr and disinfectant ; hence, why animal black is in 

 such request as a filter in sugar refineries. The finer the body, also the 

 more rapid the dissolution, because a greater surface can be acted upon by 

 water or acid; hence, why powdered feldspar is a manure, by yielding its 

 potash, ground-fossil bones and phosphates. By pulverizing the soil, the 

 farmer discounts the work of time, and by doing the same for manures, he 

 helps the efforts of the roots. — P. C. 



CHEMISTRY. 



SPECTROSCOPIC DISCOVERY OF OXYGEN IN THE SUN. 



Celestial chemistry has taken another stride forward. In a paper recently 

 read before the American Philosophical Society, and printed in the American 

 Journal of Science and Arts, Dr. Henry Draper announces the discovery of 

 oxygen gas in the sun, the fact being arrived at and verified by a long course 

 of spectroscopic observations. 



Viewed in any of its numerous aspects, this discovery is of immense 

 interest. Whether as an extension of our knowledge of solar physics, solar 

 chemistry, and the nature of the spectrum itself, or as throwing further light 

 upon the constitution of the universe ; whether as bearing upon cosmical 

 theories that have attracted much attention, or as a triumph over the difii- 

 culties of complicated experiment, or, finally, as an illustration of hereditary 

 genius in science, where a line of research opened brilliantly by the father 



