150 
2. 
3. 
4, 
5. 
REPORT—1840. 
Temperature of mines, galleries, deep wells, overflowing 
or Artesian wells, rivers at various distances from their 
source and from glaciers; the sea and lakes at different 
depths and seasons. 
Modifications of temperature, + or — immediately above 
the surface of the soil at different hours and seasons. (60.) 
Decrement of temperature at different heights, and the 
modification of the annual and diurnal curves due to ele- 
vation. (51, 57.) 
A comparison of the different instruments for measuring 
solar radiation—Leslie’s, Cumming’s, Herschel’s, Pou- 
illet’s. (61, &c.) 
6. Observations on nocturnal radiation in different states 
of the atmosphere, and towards different regions of the 
heavens (at the same angular elevation) ; comparison of 
the ethrioscope (especially the effect of metallic reflectors 
in increasing cold, questioned by Pouillet); Pouillet’s 
actinometer ; the thermo-multiplier. (79, 80, 114.) 
7. The ascertainment, by barometric measurement, of the 
elevation of a number of marked points in the neighbour- 
hood of the observer’s residence. A combination of such 
local results would give the general configuration of a 
country. The levelling (by the barometer) of the course 
of rivers, and a few of the most elevated points of the in- 
tervening mountain-chains, is most useful*. 
8. The relation of the boiling points of fluids, especially 
water and alcohol, to the barometer, and the supposed 
anomalies mentioned by Hugi. (163.) 
9. The curious anomalies in barometric measurements de- 
pending on the difference of temperature of the two 
stations (Lenz and Galle), and perhaps on the direction of 
the wind. (159.) This is an important, and, in a favourable 
situation, not a difficult inquiry T. 
10. Further comparisons of the dew-point and moist-bulb 
hygrometer are not necessary. But careful observations 
with the latter are highly desirable under all possible cir- 
cumstances. The curves of annual and daily dryness 
ought to be investigated, and the indications of the instru- 
ment reduced, not by the computation of the correspond- 
ing dew-point, but by ascertaining (from Apjohn’s for- 
* See M. Guerin’s very interesting Mesures Barométriques dans les Alpes 
Francaises, Avignon, 1829. An excellent specimen of what is here intended 
is to be found in the Comte de Raffetot’s barometric measurements in the 
valley of Baréges. See Edinburgh Philosophical Journal, January, 1837. 
+ Ramond’s Mémoires sur la Formule Barométrique cited in the former Re- 
port may be consulted with advantage on this subject. 
