304 
Proceedings of the Eoyed Society 
Anal yses. 
The following are analyses of the substances, but much re- 
liance cannot be placed on them, as they are each from a single 
analysis of a very small quantity of substance. 
I. Purple and lilac portion from interior, changing on exposure, 
giving off ammonia, insoluble in water, and depositing brown 
powder. 
II. Pale blue, interspersed with white particles. 
I. 
II. 
Cu . 
21-67 
26-77 
Zn. 
32-62 
33-76 
Cl . 
27-08 
2634 
C0 3 (from C0 2 ) 
10-10 
6T6 
NH 4 .... 
6-39 
6 84 
NH 3 . • 
212 
... 
99-98 
99-87 
On a Peculiarity of the Diurnal 
Hygrometric 
Curve at 
Geneva. By Alexander Buchan, Esq. 
In a work recently published by Professor Plantamour on the 
climate of Geneva, the hourly means of the aqueous vapour of the 
atmosphere for each month is given, deduced from observations 
made during the twenty-seven years ending with 1875. The curves 
drawn from these figures are undoubtedly the most remarkable of 
the meteorological specialties of the climate of Geneva. 
Professor Plantamour endeavours to explain the facts of the 
diurnal hygrometric curves at Geneva by the ascending and 
descending currents of air consequent on the diurnal march of the 
temperature. These systems of air currents serve to explain a part 
of the phenomena in question, — but only a part, and we think a 
very small part. A reference to the curves at other places is suffi- 
cient to show that this explanation is insufficient. There is 
another cause to which the characteristic feature of the curves 
is due, and that cause is the diurnal changes of the wind, which 
