167 
with single louvres, but sloping in an opposite direction. 
The screen was placed about twenty feet from all buildings, 
but during the winter months was, with the exception of a 
short time in the day, in the shade. Rightly or wrongly, I 
considered this screen was preferable for this climate to a 
Stevenson’s screen, and that yet observations so made were 
comparable with those made in England. 
Although my times of observation were not quite the 
same as those of Dr. Spengler, yet they admit of certain 
comparisons being made, and we find that there apparently 
was very little difference in the early morning temperature, 
though my registers seem to have been a little the lowest ; 
also in the middle of the day, the difference as a rule was not 
great, though then mine were rather the highest.* When we 
come to the moisture then the observations are more un- 
satisfactory, for while the mean would not differ very much, 
yet when detail examination is made we find very serious 
differences, sometimes in one direction, sometimes in another, 
and I have therefore in these cases compared with neigh- 
bouring places, and it is clear that sometimes the error was 
on my side, and sometimes on that of Dr. Spengler ; and, as 
we may conclude in hygrometrical measurements that the 
lower figure is the correct one, this shows that Davos is 
much drier than the figures obtained by either of us would 
seem to indicate. On mentioning this to Dr. Spengler, he 
considered that his error would arise from the bulb having 
been wetted too short a time before the observation, which 
I have already shown to be a source of frequent error. The 
detail comparison entirely bears this out, whereas it now 
seems on similar examination that my error was in the op- 
posite direction, and, therefore, although I took every pos- 
* Our published monthly means are : — 
Spengler. 
Waters. 
Difference. 
November, 1870... 
...— 1*39°C. 
... —1*0° 0. 
... 0*39. 
December, 1870..., 
... — 8'12°C. 
... — 8'20°C. 
... 0*08. 
January, 1871... 
...— 9-68°C. 
... — 9*69°C. 
... 0*01. 
February, 1871... 
.„ — 4-09°C. 
... 0*97. 
