CURRENT METERS 27 



Meters are ordinarily supported on either graduated rods 

 or on meter cablet. Standard graduated rods are best adapted 

 i.. !.. relodtiei .m.l t. depth, n.i exceeding five fert. For high 

 velocities or greater depths it is necessary to use cable of special 

 design* 



The cable must be strong enough to properly support the 



.mi* . tint "I \seiplitii*' .Id the meter in place. It must also 



.1 .mil nl high quality. The cable usually consists 



of No. 16 old code double insulated show \sm<i<\s cord, which 



\%ill properly support the weights genrr.ilU used. For those 



ii'.nal cases where heavy weight is required, an appro- 



JM ill- m. Tease should be made in the size of the cable. 



The amount !' weight to be u*ed dep. . the velocity 



of tt nt to be measured. A single ten pound weight 



will serve for the measur> -im -nt <t ordinary velocities. Thirtv 



<U \>-iuht is sufficient t<T all cases of ordinary pra< 

 A single thirty pound weight is preferable, but for convenience 

 in handling, two fifteen pound weights may be used. When 

 \\.-i-ht is used it should be in one pi<-<- and when placed 

 on the lunger the top of the weight should be not less than six 

 inches from the bottom of the cups. 



The frequem \ \\ith \\hirh the revolution of the cups will 

 .|i,.it .1 ilrp.-mU 'ii the velocity of the water to be measured. 

 For velocities under four feet per second the contact indicating 

 each single revolution >h<ul<l be selected, hut for higher \el- 

 M iiies the contact imlie.iting every fifth revolution should be 

 used. Electric Register No. 609 will record satisfactorily all 

 usual velocitie- \\jth either style of contact chamber. 



