MR. J. F. MILLER ON THE METEOROLOGY OF THE LAKE 
Of late, I have always carried with me a hygrometer of known accuracy on visit- 
ing the Lake Districts, and all experiments which 1 have made on the hygrometrical 
state of the atmosphere at considerable altitudes above the sea. tend to establish the 
law which this investigation has brought to light, by showing that the degree of 
humidity increases upwards from tlie earth’s surface, and that the condition, or com- 
bination of conditions most favourable for the condensation and precipitation of 
vapour in the greatest abundance, does obtain somewhere about 2000 feet above the 
sea level. 
It is probable that the atmosphere is generally, at or near the point of saturation, 
at and above 2000 feet; but as the air temperature decreases with every further in- 
crease of elevation, its capacity for vapour is proportionately diminished, and con- 
sequently there will be less to precipitate than at the point where the temperature of 
the air and that of the dew-point first begin to balance each other. 
From the nature of the research, it is quite impossible to obtain regular and con- 
nected observations on the hygroscopic state of the atmosphere at such great heights, 
but in course of time I hope to bring together a sufficient number of data to enable 
us to connect together some of those links in the great chain of causation which 
regulates the gradation and amount of precipitation at various altitudes above the 
earth’s surface. 
I am fully aware that the physical law indicated by these results, is at variance 
with the experiments of many careful observers, and with the inferences drawn from 
them by scientific men of the highest standing. But, with every deference to the 
opinions and deductions of these eminent authorities, it must be admitted that they 
have been arrived at from somewhat scanty materials. So far as my knowledge ex- 
tends, no investigation of any extent or continuity had been made in this department 
of meteorology previously to that set on foot in the Lake District, about three years 
ago. The facts previously on record, with few exceptions, referred to comparatively 
moderate altitudes, mostly under 1000 feet, and as some of the experiments were 
made on the mountain breasts, the results would vary greatly, according to the gra- 
dient and position of the acclivity, and as the gauges were placed either on the 
windward or leeward side of the hill ; regard must also be paid to the season of the 
year, for a gauge which in summer receives considerably more rain than the valley, 
may in winter obtain less ; and where the instruments are read off* at long intervals, 
there will be no inconsiderable loss from evaporation. Moreover, experience con- 
vinces me that little dependence can be placed on the results obtained from gauges 
stationed on the side of a hill, with whatever care they may have been secured. For 
there cannot be a doubt, that a pluviometer placed on the breast of a mountain, even 
on the windward side, will receive much less rain than it would do if stationed on a 
hill-top of equal elevation. 
Thus, the gauge at Brant Rigg in Wastdale, about 500 feet above the sea, though 
on a comparative flat, but with abruptly rising ground behind it, in the summer of 
