476 Miscellaneous Intelligence. 



rections," are most philosophically regarded as forms of one aggre- 

 gate species. The author adopts for this the name of R. Mjdro- 

 charis Spenner (1829) ; but he certainly should have retained one 

 of the Linnsean names, the most appropriate one of R. aqiiatilis. 

 He proceeds to arrange and describe the subspecific forms, admit- 

 ting 35, all but one of which bear old names. The exception is 11 

 Zobbii, from California, one of the hederaceiis group, and indicated 

 as a variety of that species by Dr. Torrey in the Botany of Whip- 

 ple's Expedition. The genuine R. hederaceus has recently been 

 detected by the late Mr. Munn, near Norfolk, Virginia, in fresh- 



Mr. Hiern states that it occurs in North America, but does not 

 say where. a. g. 



6. The Rhododendron, and '■'American Plants f by Edwaed 

 Sprague RA:tfD, Jr. Boston: Little, Brown & Co. 1871. pp. 

 187, 12mo. — One of those small and neat practical books, very 

 handsomely printed, which are so attractive ; and with reason, as 

 conveying the information which the amateur cultivator needs, in 

 a pleasant and readable form, free from all technicalities, and in- 

 deed fi-om all scientific details. And the author writes not only 

 con amore, but from abundant knowledge of Rhododendron lore 

 and culture. So great is his success that he can affirm that Rho- 

 dodendrons may be grown in New England " as easily as lilacs ;" 

 but, as subsequently qualified, only by those who will take the 

 requisite pains in the first instance. a, g. 



V. Miscellaneous Scientific Intelligence. 



1. Ventilation of Soldiers? Quarters. Special report of Acting 

 Assistant Surgeon B. F. Craig, United States Army— ajp^endix 

 to the Surgeon General's "Circular No. 4."— Dr. Craig hasmade 

 a valuable contribution to our knowledge of the general subject of 

 ventilation by his researches made at certain military posts, the 

 details of which are given in his " Special Report " to General 

 Barnes. We have compiled from this paper the accompanying 

 tabular statement of Dr. Craig's results in a form convenient for 

 reference. Dr. Craig places but little reliance on the determina- 

 tions of animal matters emanating from the human body, seeing 

 "they are so small in actual mass and of so complex and indefinite 

 a character, that they evade to a certain extent the powers oi 

 chemical titration." He therefore confines himself chiefly to J"^ 

 determination of carbonic acid (Pettenkofer's method, modified 

 slightly) and the measurements of hygroscopic moisture, tempera- 



The quantity of carbonic acid in air is increased about one 

 hundred times in passing through the lungs, or from about four 

 parts in 10,000 to four parts in one hundred of air. Mr. Edward 

 Smith's experiments have shown that a sleeping man produces 

 about four-tenths of a cubic foot of carbonic acid per hour, and 

 will therefore increase the amount of it in 1000 cubic feet of air to 



