2:^5 



and position of the rain-gauge were unimportant. The case, iiow- 

 ever, was widely different when the drop was liliewise iuHuenced by 

 wind, for then any object raised above the surface, such as a rain- 

 gauge projecting three or four feet from the ground, occasioned de- 

 flections and eddies, whereby the regular fall of the rain into the 

 collector was prevented. The Author then recommended, that in 

 all cases the gauge should be placed on the ground, with its mouth 

 on a level with a regularly trimmed grass plot, so as to prevent 

 eddies and evaporation. The form which he considered unexception- 

 able (an example executed by Mr James Bryson, 66 Princes Street, 

 being exhibited) was that of a copper cylinder, with a funnel-form 

 partition placed about an inch and a half below the mouth, having 

 an aperture for the index of a float, which rises as the rain passes 

 into the receiving portion of the lower part of the cylinder, at the 

 bottom of which is a stopcock for letting off, at times, the accumu- 

 lated water. A second cylinder of copper, closed at bottom, is pro- 

 vided, to be inserted into the ground for the reception of the gauge, 

 the latter having a shoulder or flange to prevent the entrance of 

 earth. By this arrangement the collector and receiver are equal in 

 area, so that errors of workmanship are avoided. The state of the 

 gauge is known by simple inspection of the index of the float, and 

 extreme facility of emptying and adjusting the instrument secured. 



2. On a Method of Cooling the Atmosphere of Rooms in a 

 Tropical Climate. By Professor C. Piazzi Smyth. 



After stating the case distinctly, and dwelling emphatically on its 

 importance, as shewn by individual instances in private life, and by 

 the statistics of the world at large, the author proceeded to describe 

 the various methods adopted at present in India, and shewed their 

 incapacity to meet the end proposed, as they merely agitated the air 

 already in a room, or perniciously overloaded it with moisture. 



To take the most difficult case that could occur, he chose that of 

 a country where the mean temperature of day and night, and sum- 

 mer and winter, is never below 80°, and where there could, conse- 

 quently, be no coolness in springs or rivers, or in the night air ; 

 whei-e also the atmosphere being saturated with moisture, no cold 

 could be produced by evaporation ; and under such circumstances 



