1871.] Meteorology. 281 



We have also to welcome a new and revised edition of the " Board of Trade 

 Barometer Manual," which has just appeared. This little book, which runs to 

 the length of 70 pp., contains a good deal of new matter compared with 

 preceding editions. Among other points, we may notice a chapter on " The 

 Present Condition of our Weather Knowledge in Connection with Meteorolo- 

 gical Telegraphy," by Mr. Scott ; a chapter on "The Use of the Barometer to 

 Seamen/' by Captain Toynbee ; and a short description of " The Most Usual 

 Forms of the Barometer, with some Tables for Barometrical Reductions." 

 The text is illustrated by a few woodcuts and some plates, and the whole 

 pamphlet forms a much more complete and satisfactory manual than those 

 formerly issued by the department. 



We are glad to notice that since the beginning of the year the " Shipping 

 and Mercantile Gazette " has commenced the issue of a daily wind chart for 

 these islands, the information for which is supplied by the Meteorological Office. 

 The chart is prepared on a plan devised by Captain Charles Chapman. The 

 publication of these charts is a great step in advance, and we learn that they 

 have been received with very general approval by the subscribers to the 

 " Gazette." 



The last number of the " Proceedings of the British Meteorological Society " 

 contains a paper by Mr. Dines, " On Evaporation and Evaporation Gauges." 

 The experiments seem to have been very carefully carried out; but as the author 

 of the paper himself remarks, a much more thorough investigation of the subject 

 is requisite before laws can be laid down. The mode of testing the evapora- 

 tion, on a small scale, was to place a vessel of water on one scale of a delicate 

 balance, and to counterpoise it exactly with weights. If then evaporation be 

 taking place, the weight of the water will decrease ; if, on the contrary, con- 

 densation be going on, the weight will increase. In either case, the rate at 

 which the weight changes can be measured, and also the temperature at which 

 condensation ceases and evaporation begins. Theoretically this temperature 

 should be the dew-point as given by independent hygrometrical observations, 

 and, practically, Mr. Dines found that in the saturated atmosphere of a green- 

 house the two temperatures nearly agreed ; but that in the ordinary atmosphere 

 of a room the temperature at which the water on the scale of his balance 

 ceased to increase in weight was sometimes as much as 3 or 4 below the 

 dew-point, as given by the wet and dry bulb hygrometer. Mr. Dines's evapo- 

 rating gauge is a large cistern, with a smaller cistern beside it, connected with 

 it by a pipe at the bottom, so that hydrostatic equilibrium is always preserved. 

 The level of the water in the small cistern is observed by means of a ball 

 which floats on it, and is attached to an arm hinged at the bottom of the 

 cistern. The arm may be prolonged beyond the ball, so as to describe a large 

 arc and give an open scale. The remainder of the number is mainly taken up 

 with accounts of the Auroras of October 24, 25, as observed by the several 

 assistants at Greenwich Observatory. As might be expected, the individual 

 observations correspond very well with each other, so that the notices might 

 fairly have been condensed from 16 pages into three or four. 



Mr. Blanford has published a paper " On the Normal Rainfall of Bengal," in 

 the "Journal of the Asiatic Society." Dove's notice of this region, in his 

 " Rain Tables for the Globe," contained in the first part of his " Klimatologische 

 Beitrage," is confined to the figures for 12 stations. The number of stations 

 included in Mr. Blandford's paper is 47, and the Presidency is divided into ten 

 districts. 



The principal results of the discussion are : — 



1. The rainfall of Eastern begins earlier, and is on the whole heavier than 

 that of Western Bengal, at stations equally distant from the sea, and at 

 equal heights above its level. 



2. The south-west monsoon of Eastern Bengal is probably induced by the 

 rarefaction over Thibet; that of Western by rarefaction over the Punjaub. 



3. Western Bengal receives, in addition to the normal rain of the south-west 

 monsoon, a slight precipitation during the cold season, and also some irregular 

 spring rains. 



VOL. VIII. (O.S.) — VOL. I. (N.S.) 2 O 



