Miscellaneous Intelligence. 241 
appendices, in the first of which certain topics in electricity are 
treated more fully than in the main portion of the volume, wit 
hardly consistent in quality with the rest of the work, and if, 
ndeav i i 
the historical method is kept in view throughout the book. The 
author in his preface “ acknowledges his indebtedness to the pro- 
found views of his friend, Prof. W. H. C. Bartlett, whose mathe- 
matical exposition of the unity of physical action has been the 
point of departure of his own labors.” A. W. W. 
3. On the Theory of Ventilation; by F. 8. B. Francois DE 
Cuavmont, M.D.—In my previous paper (Jan. 28th, 1875} I en- 
deavored to establish a basis for calculating the amount of fresh 
~e ge to keep an air-space sufficiently pure for health, tak- 
: ‘ 
ig the carbonic acid as the sure, The results showed that 
© Mean amount of carbonic acid as respiratory impurity In alr 
undistinguishable by the sense of ) fro h external air 
$ under 02000 per 1000 volumes. My object in the present 
Hote is to call attention to the relative effects of temperature and 
umidity upon the condition of air, as calculated from the same 
observations, 
emperature, Humidity. Carbonic aci 
63° F, 73 per cent. 0°1943 per 1000 volumes. 
nape We arrange the observations according as they differ from 
lag standard of temperature and humidity, and note the 
rd of sensation attached to each, we may ascertain how far 
