1881.] and rainfall to temperature in India. 83 



opposite character. In the first place, the very condensation of the vapour 

 which forms them, sets free a quantity of latent heat, which retards the fall 

 of temperature, that would otherwise take place in every ascending current ; 

 and such currents exist in the large majority of rain clouds, if not in 

 all; and, secondly, the solar radiation, which the cloud stratum shuts off 

 from the earth, must be partly absorbed in the evaporation of the cloud 

 surface. 



Hence, there seems to be much probability, that the temperature ano- 

 malies of the higher strata of the atmosphere, as a general rule, are of the 

 opposite character to those shown by our land observatories at low levels ; 

 but if so, the elevation at which this law holds good, must be considerably 

 greater than that at which the hill observatories of the Himalaya afford 

 the means of verifying it. 



VII. — -Description of a rain-gauge with evapometer,for remote and seclud- 

 ed stations. By H. F. Blantord, F. R. S., Meteorological Reporter 

 to the Government of India. 



(With Plate XV.) 

 [Received 25th March 1881. Read 6th April 1881.] 



In the autumn of 1879, I received, through the Government of India, 

 a description and sketch of a rain-gauge proposed by Mr. Hutchins, 

 Assistant Conservator of Forests in Mysore, for the purpose of collecting 

 the rainfall at remote and rarely visited stations, such as in certain forest 

 tracts, and other places, where there are no permanent residents, and which 

 can be visited only at longer or shorter intervals. There are, it is true, 

 several forms of rain-gauge provided with mechanism for the purpose of 

 registering the fall, but these are expensive at the outset, and if, as fre- 

 quently happens, the mechanism becomes deranged, the gauge must as a 

 rule be sent to a Presidency town or some large Government workshop for 

 repair ; involving further expense and an interruption of the record, at a 

 time, perhaps, when it is most inconvenient. 



Mr. Hutchins' idea was to provide a gauge of sufficient capacity to 

 hold the rainfall of a month or even longer period, which might be mea- 

 sured on periodical visits to the station ; and since, under such circumstances, 

 there must always (except in prolonged wet weather) be an appreciable 

 loss by evaporation, he proposed to use an evapometer with the gauge, 

 which should show the evaporation in the intervals of the measurement ; 

 which quantity, being added to the rainfall collected and measured, would 

 give the total fall in the interval. 



