CURRENT METERS 



73 



l.i in I * 



I In- n. u i.|. ..i ll....k <..ige is a great 

 itn|.!..\. in. nt i.\ri other patterns. Item 



M th.it tli>- reading* can 

 be taken !> the observer with the ^r-.it.--t 

 'poshil'l' M.l at -uii.- .1 1 -lance 



i tlu* tturface of the ttreani or diirh 



ig mrasm.-'l. I !! 



.ul\ - -*pe i. ills MI 111 tin- I .iM. where 



many of the streams art* contaminated IN 

 le -lulls .mil other uinl.-Mr.ilil.- ni.ili-n.il. 



'..iinj- it unpleasant for tin- oh 



U-t (in i rl.i-r i.. thr water. 



ll<>ok Cage is made entin-1 

 metal ami i- m k.-l plain! throughout. Th.- 

 tube is regularly true I* \,, read to 2.2 feet 

 but may bt made longer if desired. It i- 

 graduated to fn-t. tnith- ami hiindmlth-. 

 and is read to thousandths by a venn< t. 

 which is capable of fmr adju^tim-nt l\ 

 in. a ns of a slow motion screw. Elongated 

 holes in th< -m-h means for bolting 



the gage to the side of the flume. The 

 hook is adjustable within the tul>e and 

 allows for a movement of 12 inches 

 imlrpeml.-nt of the gage, ihu- permitting 

 it to be set accurately to the exact surface 

 of the water. 



: 





LI I M Mil. d 1:1 > ^ HOOK CAGE 



The hook gage is used in a box attached to a flume at any 

 convenient point near the >%<-ir. the water I nun the flume In-ing 

 conveyed to the box by rubber or lead pipes, thu- imlu.tting 

 the precise level of the water in the flume, tho surface of the 

 water in the box being at rest 



When the depth of the water passing over a weir is required, 

 the exact level of the crest of the wrir >houltl be taken by a 

 leveling instrument and rod, and marked by a line drawn in the 



