710 



THE POPULAR SCIENCE MONTHLY 



Pluckiger and Daniel Hanbury, F. R. S. Lon- 

 don : Macmillan & Co. 1879. Pp. 803. $5. 



A Handbook of Double Stars. By Edward 

 Crossley, Joseph Gledhill, and James M. Wilson. 

 Loudon : Macmillan & Co. 1879. Pp. 464. $6. 



The Microscope in Medicine. By Lionel S. 

 Beale. Philadelphia: Lindsay &Blakistou. 1878. 

 Pp.528. $7.50. 



A Treatise on Vocal Physiology and Hygiene. 

 By Gordon Holmes, P. R. C. P. Phiiadeiphia : 

 Presley W. Blakiston. 1880. Pp. 266. $2. 



The Refutation of Darwinism and the Con- 

 verse Theory of Development. By T. Warren 

 O'Neill. Philadelphia: Lippincott & Co. 1880. 

 Pp. 544. $2.50. 



Sunshine and Storm in the East. By Mrs. 

 Brassey. With upward of a Hundred Dlustra- 

 tions. New York: Henry Holt & Co. 1880. 

 Pp.448. $3.50. 



England: her People, Polity, and Pursuits. 

 By T. H. Escott. New York : Henry Holt & 

 Co. 1880, Pp.625. $4. 



The Metaphysics of the School. By Thomas 

 Harper. London : Macmillan & Co. 1879. Vol. 

 I., pp. 592. $5. 



A Manual of the Antiquity of Man. By J. D. 

 Maclean. Cincinnati : Robert Clark & Co. 1879. 

 Pp.159. $1. 



How to educate the Feelings or Affections. 

 By Charles Bray. Edited by Nelson Sizer. New 

 York: S. R. WeUs&Co. 1880. $1.50. 



POPULAR MISCELLANY. 



Action of Organic Acids oa Minerals.— 



At a recent meeting of the New York Acad- 

 emy of Sciences, Professor H. Carrington 

 Bolton, of Trinity College, Hartford, com- 

 municated the results of a continuation of 

 his researches on the behavior of minerals 

 with organic acids. In a previous paper 

 (read in 18*77) he gave the reactions of 

 ninety-five minerals with citric acid ; in the 

 present paper he extended the investigation 

 to two hundred species. Dr. Bolton stated 

 that citric acid has a power of decomposing 

 all classes of minerals little less than that 

 possessed by hydrochloric acid, and that 

 this very difference in degree gives the or- 

 ganic acid an advantage over the mineral 

 acid in the determination of species. Be- 

 sides treating the minerals with a saturated 

 solution of citric acid, he examined the ac- 

 tion of the same solution, to which solid 

 sodium nitrate is added. This mixture 

 proves to be a very powerful solvent, dis- 

 solving bismuth, antimony, arsenic, copper, 

 lead, tin, mercury, and silver, and nearly 

 all the natural sulphides. The addition of 

 solid potassium iodide to the solution of 

 citric acid also greatly increases its decom- 

 posing power. Applying these reagents to 

 minerals, Dr. Bolton obtained the following 



results : 1. Complete solution of carbonates, 

 with liberation of carbonic - acid gas. 2. 

 More or less complete decomposition of 

 oxides, phosphates, etc. 3. More or less 

 complete decomposition of sulphides, with 

 liberation of sulphuretted hydrogen. 4. 

 Decomposition of sulphides, with oxidation 

 of the sulphur. 5. Decomposition of sili- 

 cates, with separation of slimy or gelatinous 

 silica. 6. Decomposition of certain species, 

 with formation of characteristic precipitates. 

 7. Wholly negative action. The exact be- 

 havior of each of the two hundred minerals 

 was given in a printed table, copies of 

 which the speaker distributed to the audi- 

 ence. The application of this investigation 

 is twofold: 1. The utility of the methods 

 in field-work, owing to the portability of 

 the reagents in a dry state; and, 2. The 

 relation of these reactions to the geological 

 work of the organic acids of the soil. The 

 latter point is of much importance, and 

 merits further researches. 



How Snakes shed their Skins.— Under 

 the title "About Snakes" in this depart- 

 ment of our last number, we gave Dr. H. F. 

 Hutchinson's mode of accounting for the 

 way snakes get out of their old skins. Pro- 

 fessor Samuel Lockwood, of Freehold, New 

 Jersey,, has witnessed the process, and, froni 

 a description of it given in his own inimit- 

 able style in a late number of "Nature," 

 we gather the following interesting facts, 

 which, as will be seen, do not support the 

 hypothesis of Dr. Hutchinson: A female 

 snake had already begun to cast her skin 

 when Professor Lockwood made his first ob- 

 servation, but the process was going on very 

 slowly. The skin was slightly torn at the 

 snout, and the head and a little of the neck 

 were denuded. As it separated from the 

 neck it had a sort of "back-creeping as- 

 pect " ; there was no rubbing against exterior 

 objects, and indeed it looked as if the change 

 going on might be the work of an invisible 

 power. Closer observation showed that 

 there was a systematic alternate swelling 

 of the body at the neck of the skin, thus 

 stretching it, and making a shoulder in front 

 of this neck, each swelling pushing the loos- 

 ened skin a little backward. As soon as the 

 process reached the larger ribs it went on 

 more rapidly, and in the following way: 



