DR. B. A. SMITH ON MINIMETBIC ANALYSIS. 187 



air is so filled as to smell musty^ although there may be a 

 fall measure of oxygen present ; but if it is to be purified^ 

 the wind must blow and oxidize at the same time that it 

 carries away mechanically. And if it removes, it must 

 remove it to a spot. It is difficult to escape the presence 

 of these minute bodies. • 



One plant seemed to me to resemble the yeast plant, 

 and one to resemble that found during the formation of 

 vinegar; but neither I nor Mr. Dancer could on trial 

 prove any fermentation. When treated with perman- 

 ganate of potash, 150 grains took 0"6 cub. centim. of a 

 solution; some days afterwards o"] without acid; with acid 

 the same amount took i*i cub. centim. of permanganate, 

 and after ten days I'g. It was undergoing some chemical 

 action. The commonest observation would lead any one 

 to say with Bacon, ^^out of question it is man^s sweat 

 putrefied.^-* , 



XII. On Minimetric Analysis. 

 By R. Angus Smith, Ph.D., F.R.S., &c.. President. 



Read April 4th, 1865. 



Tests for Carbonic Acid and of Ventilation. 



Although the only impurity in air is not carbonic acid, as 

 a rule the best chemical test for ventilation of rooms ren- 

 dered impure by exhalations from the person is the presence 

 and quantity of this gas. It will be seen in a former paper 

 that baryta- and lime-water were tried for a long time in 

 various ways, and after various stages became accurate in 

 the able hands of H. Saussure ; simple, and in theory com- 

 pletely accurate, in the hands of Mr. Hadfield ; and at last. 



