S REPORT AJriJ OfiS^if ATtONS ON 



Upright graduated rod attached to a flod.t covering the surface 

 of the water, which itidicates the depth of rain cailght within 

 the Cylinder. 



Objections have been made to this fbrtn of gauge from 

 the effect alleged to be produced by thd rod as it rise^ 

 above the level of the top of the cylinder, exposing addi- 

 tional surface, and adding in that rnahner tO the collectitig 

 surface of the gauge. 



£xperitrients have befen ttidde fdt sotfie years by Ml'. 

 Wood, the engitiecft to the Ashton atid Peak Forest Canals, 

 f o ascertain the effect produced hy tods standing sotrie height 

 above the top of the gauge. 



That a Sensible effect is produced, incre^irlg the quantity 

 of water caught, appeal^ to be cleariy established from thes^ 

 experiments ; but they do liot afford any assistance in det^f- 

 minidg the hfeigbt at which the rod begins to affect the 

 accuracy of the register, not do they fbrnish atiy data frotil 

 which to calculate the ptopoi*tionate increased quantity du^ 

 fo the elevation of the rod. 



For instariCe, in one situation a rod Of 1 inch ifli did- 

 iiietef, fetauditig 24 inches afeov'e tfce ib^ Ht the gaugd, 

 collected in 12 months 3-18 Inches Of taiti ; While in atiothei* 

 ptaCe a tod of the same diametef, but Only ISf iriche^ ^otig^ 

 collected in the same time 27 -S^ inches, the quantity of raiii 

 as indicated by the raia gauges beitig respectitely 4d'75 dtid 

 61-30. 



Again, a staff or rod of 2 inches diameter, and l8| itiches 

 long, collected in 12 months 20-67 inches, the raiii being 

 apparently at that place SS'SS'. At another plaCC^ a rod at 

 fhe same diametef and length, where the rairi appears td 

 have been 35 -85, collected in the same period 58 '99 inched. 



These differences are enormous, and ap^iarently anac^ 

 countable. 



dii cohdderation, it appears probable that the rod wllf 

 produce fad feasible effect until it rises tO a height greatW 



