164 
in deep snow, exposed to the sun* from 9.15 a.m. to 3 p.m., 
the loss was 0*109 mm., or a trifle less than from the ice in 
the shade during the same time, where, however, the tem- 
perature was above freezing for about an hour. The loss 
from the ice in the 24 hours was 0*429 mm. This form of 
observation is probably worth constant repeating, and next 
winter I purpose continuing the observations, with some 
important modifications which experience has shown to be 
advisable. 
Of course the evaporation must be small when the tem- 
perature is low (although somewhat accelerated here by the 
low barometrical pressure). The figures for Paris and 
Vienna are : — 
Paris, 1875. Vienna, mean of many years. 
December, 11 mm. ... 18 mm. 
January, 34 mm. ... 13 mm. 
In Paris, the yearly total is 776 mm. ; in London, about 
650 mm. 
The popular belief here is, that the evaporation in Davos is 
extremely rapid under all circumstances, and this is no mere 
theoretical question, for the false belief that newly built 
houses dry miraculously rapidly has led to serious results, 
and, probably through this error, the grave has closed over 
some whose life might otherwise have been prolonged. 
The south side of a house into which the powerful winter 
sun pours is dried very rapidly, but the rest of the house 
dries but slowly; and when here eleven years ago, I ex- 
amined several houses just built, and tried to combat the 
false ideas then held. 
This winter a large cafd and theatre, into which very 
little winter sun enters, was opened immediately upon 
completion, and the results were that the larger propor- 
tion of patients in the hotel to which these buildings belong 
were in a few days suffering from colds, some sufficient to 
* The solar radiation on the 9th as measured by a black bulb ther- 
mometer in vacuo was 104° F. The day was cloudless. 
