OBSERVATIONS TAKEN IN INDIA. 
345 
t*. 
t'. 
t—t’. 
1st series. 
0 
1st experiment 14'66 
7‘28 
o 
7*38 Centigrade thermometer. 
2nd experiment 14'96 
4*33 
10*63 Centigrade thermometer. 
2nd series. 
1st experiment 2T48 
10*78 
10*70 Centigrade thermometer. 
2nd experiment 21 ‘70 
8*56 
13*14 Centigrade thermometer. 
In Fahrenheit’s scale. 
58*37 
45*10 
13'27 
58*93 
39*79 
19*14 
70*66 
51*40 
19*26 
71-06 
47*41 
23*65 
In the first series, in the second experiment, the wind blows faster than in the first, 
and the wet bulb is reduced nearly 3°, and the difference between the wet and dry 
bulbs is increased from 7°‘38 to 10°'63, while the temperature of the dry bulb is only 
raised 0°'30, In the second series the temperature of the wet bulb is reduced from 
J0°‘78 to 8°‘56, and the difference between the wet and dry is increased from 10°'70 
to 13°' 14, while the temperature of the dry bulb is only raised (f 22. Upon these 
experiments M. Regnault says, “ On voit que, pour une meme temperature t les 
temperatures t' dependent beaucoup de la vitesse du courant d’air” (p. 209) ; and he 
further says (p. 210) that these depressions are less than he has found on other occa- 
sions with an increased velocity of the air ; and on using' dry air he found the depres- 
sion ^'=13°‘52 instead of 5°'91, and another depression of 15°'60 instead of 
8°'60. M. Regnault gives other experiments, and finishes by saying, “II resulte de 
tout ce qui vient d’etre dit, que I’agitation de fair doit exercir une influence tres- 
sensible sur les indications du psychrometre” (p. 211). The truth of M. Regnault’s 
experiments are borne out by the experience of families in the Deccan (and no doubt 
elsewhere) in India in the fair season, who cool their wine and beer by the following 
simple process down to a temperature the cold of which makes the teeth ache in 
drinking. At any time of the day a thick layer of straw is put down on the ground 
in the shade of a building, but not in the lee of the wind. The bottles of wine or 
beer to be cooled are put upon the straw, some more straw is thinly and lightly 
shaken over the prostrate bottles, and the mass is sprinkled at intervals with water 
through the nozzle of a watering-pot with very fine apertures, thus dewing as it 
were the straw ; the force of evaporation and the consequent cold is proportioned to 
the velocity and dryness of the wind ; but even with a moderate wind the tempera- 
ture of the liquors is soon greatly lowered ; and in certain hot and therefore parching 
winds, even at a temperature of the air ranging from 85° to 90° Fahr., I have often, 
at Ahmednugger, had the temperature of the wine or beer (judging from my sensations 
at the moment) approaching to the freezing-point -f-. In this cooling process we have 
* t. Temperature of dry thermometer, t'. Temperature of wet bulb. 
t My sensations deceived me. While this paper is going through the press, I have received from a friend, 
commanding the Artillery at Ahmednugger, the following results of experiments he made at my request, with 
MDCCCL. 2 Y 
