Reduction of Meteorological Tables in the Doab. 431 



being 2.85° higher than that of 1838. The amount of depression 

 below the Annual Mean exceeds that of elevation above it, by about 

 an average of 6°, and it will be observed, that generally the Mean 

 Temperature of the month of October represents most closely that 

 of the whole year. 



In passing now to the discussion of the Pluviometric results, and 

 the observations on the directions of wind and variations of weather, 

 I may remark that in respect to the latter, Mr. Brew's Registers do 

 not admit of the same detail as was given from the Kulsea observa- 

 tions by Mr. Pigott, since he has scarcely, if at all, attended to 

 the state of the weather, and hence no data are furnished by which 

 the proportions of its varieties can be estimated. 



The rain guage employed at Surrowli was of precisely similar form 

 and dimensions to that used at Kulsea. It likewise stood at a 

 height of about 5 feet from the surface of the ground. The correction 

 is applied for the effect of the displacement and consequent elevation 

 of the water in the tube, caused by the insertion of the measuring 

 rod ; but as it is very thin, the error caused would be small, and 

 when an opportunity occurs, I will endeavour to ascertain its exact 

 amount. Rain guages fixed permanently in a vertical position, are 

 liable to another source of error, namely, the effect of winds in alter- 

 ing the direction of falling rain, so that the receiver of the guage no 

 longer continues perpendicular to the line of direction in which the 

 rain is falling. Hence, when the wind drives the rain in an oblique 

 direction, the quantity received in the guage cannot be considered 

 strictly proportional to the entire quantity falling, since a consider- 

 able portion of the shower, which, had there been no wind, would have 

 fallen into the receiver, would, under the circumstanjces supposed, be 

 carried past it. Some experiments have I believe been made, to indi- 

 cate the precise oblique effect of winds on the quantity of rain as 

 shewn by guages, but I have not yet been able to see them. The 

 point is one meriting attention, and any numerical determination 

 would be highly interesting. 



