7H 



THE POPULAR SCIENCE MONTHLY. 



Physic8 in Pictures. Witli Thirty Colored 

 Plates for Ocular Instruction. By Theodore Eck- 

 ardt and A. H. Keane. London : Edward Stanford. 

 Text, pp. 20. 7«. M. 



Common -Sense Binder. New Torkr Asa L. 

 Shipman's Sons. 



Hints on the Drainage and Sewerage of Dwell- 

 ings, By William Paul Gerhard. New York : 

 William T. Comstock. Ife84. Pp.802. Illustrated. 

 $2.50. 



Land and its Eent. By Francis A. Walker, 

 Ph. D , LL. D. Boston : Little, Brown & Co. 18S3. 

 Pp. 282. 75 cents. 



A Bachelor's Talks about Married Life and 

 Things Adjacent. By William Aikman. D. D. 

 New York: Fowler & Wells. 1884. Pp. 2T3. 

 $1.50. 



The Philosophy of Self-Consciousness. By P. 

 F.Fitzgerald. Cincinnati : E. Clarke & Co. 1883. 

 $1.26. 



Electricity, Magnetism, and Electric Telegraphy. 

 By Thomas D. Lockwood. New York: D. Van 

 Nostrand. 1883. Pp.877. 



For Mothers and Daughters : A Manual of Hy- 

 giene for Women and the Household. By Mrs. E. 

 G. Cook, M.D. New York: Fowler & Wells. 

 Pp.292. Illustrated. $1.50. 



Geological Survey of Alabama : Eeport for 

 Years 1881 and 1882. By Eugene Allen Smith, 

 Ph.D. Montgomery, Ala.: W. D. Brown & Co. 

 1883. Pp. 615, with Maps. 



Second Biennial Eeport State Board of Health 

 of Iowa for Fiscal Period ending June 80, 1888. 

 Des Moines : George E. Eoberts. 1888. Pp. 417. 



The Eolations of Mind and Br.ain. By Henry 

 Calderwood, LL. D. Second edition. London : 

 Macmillan & Co. 1884. Pp. 627. 



Chemistry, Inorganic and Organic, with Experi- 

 ments. By Charles Loudon Bloxam. From the 

 fifth and revised English edition. Philadelphia : 

 Henry C. Lea's Son & Co. 1883. Pp.738. Cloth, 

 $3.75; leather, $4.75. 



First Eegistration Eeport of the State Board of 

 Health of Iowa, for the Year ending October 1, 

 1881. Des Moines: George E. Eoberts. 1883. Pp. 

 811. 



The Field of Disease : A Book of Preventive 

 Medicine. By B. W. Eichardson, M. D., F. E. 8. 

 Philadelphia : Henry C. Lea's Son & Co. 1884. 

 Pp. 737. Cloth, $4 ; leather, $6 ; russia, $5.50. 



POPULAR MISCELLANY. 



Sub-aerial Decay of Rocks. — Professor 

 T. S. Hunt publishes, in the "American 

 Journal of Science," an elaborate paper on 

 the " Decay of Rocks," in which he insists 

 that recent geological studies afford evidence 

 that a sub-aerial decay both of silicated 

 crystalline and calcareous rocks has taken 

 place universally and from the most ancient 

 epochs, and that it was very extensive in 

 pre-Cambrian times. He further insists that 

 the materials resulting from this decay are 

 preserved in situ, in some regions by over- 

 lying strata ; in others by the position of 

 the decayed material with reference to de- 

 nuding agents ; and that the process of de- 

 cay, though continuous through later geo- 

 logical ages, has, under ordinary conditions. 



been insignificant in amount since the gla- 

 cial period, on account of the relatively short 

 time that has elapsed, and also, probably, 

 on account of changed atmospheric con- 

 ditions in the later time. The process of 

 decay, he believes, " has furnished the ma- 

 terials for the clays, sands, and iron-oxides 

 from the beginning of Palasozoic time to 

 the present, and also for the corresponding 

 rocks of Eozoic time, which have been 

 formed from the older feldspathic rocks by 

 the partial loss of protoxide bases. The 

 bases thus separated from crystalline sili- 

 cated rocks have been the source, directly 

 and indirectly, of all limestones and car- 

 bonated rocks, and have, moreover, caused 

 profound secular changes in the constitu- 

 tion of the ocean's waters. The decay of 

 sulphureted ores in the Eozoic rocks has 

 given rise to oxidized iron-ores, and also to 

 deposits of rich copper-ores in various geo- 

 logical horizons." Finally, Professor Hunt 

 maintains that " the rounded masses of crys- 

 talline rock left in the process of decay 

 constitute not only the bowlders of the 

 drift, but, judging from analogy, the simi- 

 lar masses in conglomerates of various ages, 

 going back to Eozoic time ; and that not 

 only the forms of these detached masses, 

 but the outlines of eroded regions of crystal- 

 line rocks, were determined by the preced- 

 ing process of sub-aerial decay of these 

 rocks." 



" Colds." — The views of Dr. Page on the 

 subject of " catching cold," published in the 

 " Monthly " for January, having been sharp- 

 ly criticised as unsound and extreme, we 

 give below an extract on the same subject 

 from the London " Lancet," a scientific med- 

 ical authority of the highest grade: "A 

 person in good health, with fair play, easily 

 resists cold. But when the health flags a 

 little, and liberties are taken with the stom- 

 ach or the nervous system, a chill is easily 

 taken, and, according to the weak spot of 

 the individual, assumes the form of a cold, 

 or pneumonia, or, it may be, jaundice. Of 

 all causes of ' cold,' probably fatigue is one 

 of the most efiBcient. A jaded man coming 

 home at night from a long day's work, a 

 growing youth losing two hours' sleep over 

 evening parties two or three times a week, 

 or a young lady heavily ' doing the season,' 



