370 REPORT—1862, 
ence had disclosed the mistake, the writer always recorded three readings, 
corresponding to one, two, and three minutes of exposure. 
The season of 1860 was unusually inclement, and the sky rarely in fayour- 
able condition, so that in the course of about eight weeks the writer obtained 
but thirty-nine observations, of which the large majority were taken under 
unfavourable circumstances, and must therefore be rejected. 
In 1861 fifteen observations were made in the Western Pyrenees under 
more favourable conditions. 
In addition to the above, seyeral observations made in 1860 by the Rey. 
T. G. Bonney, Mr. R. B. Hayward, Rey. F. J. A. Hort, Mr. A. T, Malkin, and 
the Rey. Leslie Stephen have been communicated by those gentlemen to the 
writer. Excluding those fairly open to suspicion, the results are registered in 
the annexed Table (I.). An accurate comparison of these results would involve 
as one element the altitude of the sun at the moment of each observation, 
but the sources of error are too many and considerable to make this worth 
the requisite trouble. All that can fairly be inferred from the Table is that 
the sun’s rays produce a greater effect on the black-bulb thermometer at 
higher than at lower levels, the difference, though quite perceptible, being not 
considerable in amount. It is true that the highest reading out of twenty- 
four observations by the writer recorded in the Table was at Eaux Bonnes, 
only 2458 feet above the sea; but without considering the probability that 
that reading was exaggerated by the radiation of heated bodies (walls, &c.) 
near the thermometer, it will be observed that it was made at 20 min. before 
noon on July 25, and does not therefore indicate as great an effect of solar 
radiation as the observations made on the Schleeren (8399 ft.) at 1.10 p.m. 
on August 25, or on the Bréche de Roland (9200 ft.) at one hour and a quarter 
before noon on August 16. 
3. As might, perhaps, have been anticipated, the attempt to trace the 
propagation of disturbances in temperature by means of a network of obser- 
vations covering a considerable tract of mountain country resulted in complete 
failure. Even if the observers had been more numerous and more diligent 
than they were, the disturbing effects of local causes are far more serious 
than was apprehended. The effects of vicinity of the soil in raising the 
indications of the thermometer by day and lowering them by night, are not 
yet as fully measured or appreciated as they ought to be, and it is question- 
able whether the observations made at fixed observatories are as nearly com- 
parable as they are commonly supposed to be. Among other authorities on 
this point, a recent memoir by Mr. Charles Martins might be referred to as 
showing how important is the effect of slight differences of level on the 
nocturnal indications of the thermometer, 
The welcome intelligence that the Swiss men of science are about to esta- 
blish fixed stations for systematic observations of the thermometer and other 
meteorological instruments throughout the territory of the Confederation 
makes the disappointment on this head less important, as it is probable that, 
with requisite skill and caution in observing and reducing the results, the 
plan now believed to be definitively adopted will much enlarge our knowledge 
of Alpine meteorology. 
4, Observations on the temperature of the soil at and near to the surface 
in mountain countries are of considerable interest from their bearing on the 
distribution of animals and plants. It is not too much to say that if such 
obseryations had been available, M. Alphonse DeCandolle would have been 
led to modify seyeral of the conclusions stated in his standard work on 
