SCIENTIFIC SUMMARY. 
201 
them as indications of any other change, the author ascribes them to errors of 
experiment which became the greater in these cases from the fact of his having 
a more limited quantity of water to work with (less than one litre) than is 
desirable for experiments of these kinds. The results are very accordant 
when compared with the hitherto published analyses. They support the 
view held by the author that the amount of lime carbonate present in sea- 
water shows but slight variation. His results do not accord with those of 
J. Davy, who believed that the open sea contained little or no lime carbonate. 
And we are, moreover, not driven to believe the views pronounced by 
Forchhammer, that the sea animals which have shells are able to convert 
the lime sulphate of sea-water into carbonate. The waters of different 
regions appear to mix very rapidly and readily. 
The Ammonia and Nitric Acid in Atmospheric Deposits. — In the year 1875 
at the agricultural station in Munich, and in 1876 and 1877 at Tisis, near 
Feldkirch in Yorarlberg, W. Eugling made a number of determinations of 
these constituents in the rain, and the results are given in his report in 
Biedermann’s “ Centralblatt fur Agriculturchemie,” 1878. The amount of 
combined nitrogen appears from the results to vary considerably according to 
the locality where the rain was collected ; the nitrogen compounds which 
are brought down to the soil in the immediate neighbourhood of large towns 
are probably considerably greater. And the amount which fell in the 
months when the rainfall was small was higher than in months when 
the aqueous deposit was more abundant. These results confirm those of 
Boussingault’s researches. The average amount of the nitrogen in the pre- 
cipitates which were collected in Tisis, while lower than that in the Munich 
deposits, is greater than that of Paris, where in 1858 Boussingault found 
0-00163 gramme to the litre. In 1876 the average monthly yield at Tisis 
was 0*00320 gramme per litre, the maximum yield being in October 
0*00620 gramme to the litre, and the minimum 0*00182 gramme per litre 
in April. In the year 1877, with the exception of September, the mean 
yield of ammonia was 0*00238 gramme per litre, the maximum being in 
November 0*00520 gramme, and the minimum in April being 0*00121 
gramme per litre. In addition to this, it was found that the amount of nitric 
acid in 1876, with the exception of December, was in the mean 0*00192 
gramme to the litre, the maximum being 0*00431 gramme in October, and the 
minimum 0*00085 gramme in January; and in the year 1877 the mean yield 
was 0*00160, the maximum in November being 0*00264, and the minimum 
in December 0*00092. In the case of Munich the mean for the month of 
March was 0*00366 gramme of ammonia and 0*00169 gramme of nitric acid 
per litre ; and during April, on the other hand, 0*00414 gramme of ammonia 
and 0*00185 gramme nitric acid per litre. It was noticed that during those 
months when the ozone reaction was strongest the amount of ammonia, 
and nitric-acid-nitrogen were most nearly equal, which points to the conclu- 
sion, that at these times more ammonia nitrate and less ammonia carbonate 
are formed, not absolutely, but in relation to each other. 
Formation of Felspars Artificially. — F. Fouque and M. Levy have com- 
municated to the Academy of Sciences of Paris, the details of the process 
by which they have succeeded in preparing a suite of felspars, analogous to 
those which occur in eruptive rocks. They employ either natural porphy- 
