NOW READY 



THE PHYSICS OF THE AIR 



by 



William J. Humphreys, Ph.D., 



Professor of Meteorological Physics 

 United States Weather Bureau 



A rational and deductive treatise on the physics 

 of the atmosphere. 



Of great value to meteorologists, physicists and the aviator. 



678 pages, many illustrations, index, 8vo. 

 Price $5.00. 



Address orders and inquiries to 



THE FRANKLIN INSTITUTE 



PHILADELPHIA. U. S. A. 



The American Journal of Science 



Contributors are requested to revise their manuscript with special care with 

 reference to the use of the linotype machine ; changes involving overrunning are 

 expensive. In general, the publisher cannot undertake to assume the cost of more 

 than minor corrections in the proof. All corrections should preferably be made in 

 ink. 



Foot notes should be numbered consecutively from 1 up. 



The following is an example of the system of references employed, the volume being 

 given in heavy faced type : 



Am. J. Sci., 44, 249, 1917. The year should be given in every case; this renders a 

 series number unessential. 



Thirty separate copies of each article will be furnished to the author free of cost 

 and without previous notice from him. They will be provided with a plain cover 

 (but with reference to volume and year). If the author orders separate copies, they 

 will be understood to be in addition to the thirty mentioned above, and he will 

 receive a bill for the extra expense involved, as also for that of a printed cover (with 

 title, etc.), when this is specially ordered. 



The charge for reprints will be made as moderate as possible, consistent with the 

 present high cost of printing, binding, engraving and paper. 



IW A TEN VOLUME INDEX 



to volumes 41 to 50 will be ready in January 

 Price $2.00 in advance ; edition small ; order early ! 



