953 



In this communication are given the results of the observations of 

 the quantity of rain which has fallen during the year 1849 at twenty 

 stations in the valleys, and six mountain stations, varying in altitude 

 above the sea from 500 feet to 3166 feet. There is also given a 

 table of the temperature at Seathwaite in Borrowdale during the 

 year 1849. 



With reference to the mountain gauges, the author observes that, 

 on the whole, the results are similar to those of the three preceding 

 years, but, as might be looked for in a dry year like the past, the 

 quantities of rain deposited at the various stations are more nearly 

 equal than usual. With respect to the temperature, he observes that 

 the statement he made in his last communication, that the inhabit- 

 ants of the Lake District valleys enjoyed a milder and more equable 

 climate than the residents in the open country, and particularly in 

 the winter months," is confirmed by the thermometrical results of 

 the present winter (1849-50). 



3. "On the relation of the Air and Evaporation Temperatures 

 to the Temperature of the Dew-Point, as determined by Mr. 

 Glaisher's Hygrometrical Tables founded on the factors deduced 

 from the Six-hourly observations made at the Royal Observatory, 

 Greenwich." By J. F. Miller, Esq., F.R.A.S. Communicated by 

 Lieut.-Col. Sabine, R.A., For. Sec. R.S. 



After pointing out the importance of the hygrometer, both in a 

 scientific and a practical point of view, the author goes into the 

 question of the advantages and disadvantages attending the use of 

 Daniell's hygrometer, and the relative merits of this instrument 

 and the dry and wet- bulb thermometers. Although satisfied of the 

 accuracy of Mr. Glaisher's Tables (founded on the Greenwich Ob- 

 servations), which show at once the relation of the temperature of 

 evaporation to that of the dew-point, he was unwilling to abandon 

 the use of Daniell's apparatus for that of the wet and dry-bulb ther- 

 mometers, slight as is the trouble of observing them, without personal 

 experience of the correctness of the tables from which the dew-point 

 was to be deduced. He therefore instituted a series of perfectly com- 

 parable observations by the two methods, and in this communication 

 gives the results obtained from them during a period of twenty 

 months. From a comparison of the dew-points determined by the 

 two methods, he concludes that the results show in a striking man- 

 ner the extreme accuracy of Mr. Glaisher's Tables, and afford ad- 

 ditional testimony to the value of the Greenwich Hygrometrical 

 Observations, and the resulting formula on which those tables are 

 founded. 



The author then refers to the subject of evaporation, and gives 

 the results of his own observations at Whitehaven during six years, 

 viz. from 1843 to 1848 inclusive. From these he states that the 

 mean annual amount of evaporation is 30*011 inches; and the mean 

 quantity of rain for the same period being 45*255 inches, the depth 

 of the water precipitated exceeds that taken up by evaporation, on 

 the coast in latitude 54|°, by 15*244 inches. 



