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was carefully removed and analyzed by the authors. The results 
follow in tabular form. 
; Al, O Alkaline 
SiO. Fe, On CaO sulphates. 
Weak baryta solution..... 0.0045 0.0009 None 0.0024 
Stronger “ sean s 0.0094 0.0012 None 0.0009 
’Percentage composition of Alkaliesas Na,O 
therclass used meget azster: 69.95 2.57 17.21 10.27 
The authors’ conclusions regarding these results are stated by them 
as follows: 
1. Aweak baryta solution acts with relative rapidity on the glass of the 
Winchester quarts (and probably exercise an appreciable action on most vari- 
eties of glass), dissolving silica and alkalies, and smaller quantities of alumina 
and ferric oxide, but no lime. 
2. A stronger solution dissolves more silica but less alkalies, about the 
same amount of alumina and ferric oxide, and also, as in the previous case, 
no lime. 
An appreciable effect is shown by the authors in the titration of 
Ba (OH), after remaining in contact with the glass ; and also on the 
presence of alkaline or soluble silicates on the delicacy of the phenol- 
phthalein color reaction during titration with an acid. 
Similar tests conducted on silica with a weak solution of baryta 
water indicated a similar action as the glass. Some very interesting 
quantitative results are recorded. 
PART II: 
Part II is treated in two sections, and makes up the bulk of the 
memoir. More than twice the space is given to it (106 pages exclu- 
sive of the appendices and bibliography) than is allotted to Part I, 
which is disposed of in 50 pages. Part II consists of a review and 
criticism of all authentic and trustworthy data collected from all 
sources and arranged in tables, which bear on the amount and distri- 
bution, and the factors controlling the distribution of carbonic anhy- 
dride in the atmosphere under varying conditions. It is more than an 
ordinary compilation in that the data are discussed fully but briefly 
and the conclusions warranted are concisely stated. It is not possible 
