—24— 
vestigation. Its sides are inclined at a slope of one-fourtd 
horizontal to one vertical. 
The most complete experimental investigation of the 
fheTlr YTf ° Ve [ '^ e T S has been made b >' Americans, anc 
the adopted formula is due to one of them. To the carefu 
fcaTwT r-‘u 6 h te - JaS - B ‘ prancis - Past Resident Amer 
ican Society Civil Engineer, Honorary Member Americar 
Society Irrigation Engineers, of Lowell, Mass., is duetheordi 
nary form ot the equation of the weir, and to his careful work 
i Y r ^ u lc science owes much. At Lowell were located a num- 
manufacturing enterprises drawing their water from 
the Mem mac river Their combined capital was over thi t- 
teen millions of dollars. It became necessary to determine a 
more definite measurement of the water,and Francis’ exper¬ 
iments were instituted for this purpose. Carried on with all 
the appliances and conveniences which the capital interested 
ore L'TSL T Permed Sh sue J 
they ale above‘"uid™"” 0 " “ ml " U,e ” orces of error - 
basiLbfwWW^ ‘ n SUCh e ^P eriments is ^ obtain a suitable 
basin in which to measure the water. In this case Francis 
was fortunate in having one suitable in the Lower I ocks 
lhe°weir be de ,? ected at wil > after passing’ 
filled leal-c: ctn ° C , Was c ? re ^YHy prepared. Cracks were 
filled’, n S T! tOPPed ’ e ^ en , th = de P resslons about nail heads 
up. 1 he remaining leakage was ascertained by exper- 
Figure 6. 
iment. The slight increase in capacity due to bulging when 
full was ascertained. The total capacity of the basin when 
9/2 feet deep was over 12,000 cubic feet. 
inin^X^ inai T SSt ° f , e ^P erirtlents was made for determ- 
ng the pioper form ot the equation of the weir and after 
this was determined the main experiments were devoted to 
hndmg the numerical value of the coefficient of the formula 
•Sndar7w-ffi ! ^ Ca r d h | S ex P erim ents has since been 
Tfl 7 l the limits indicated by him. If one observes 
the flow of water through an orifice he will notice that the 
erTcontractiem at the TT ° r *■ sub ^ lat- 
erai contraction. If over a weir, the sheet of water becomes 
thinner immediately below the crest, as in Fig. 6 or is sub¬ 
ject to a vertical contraction. By taking separate account of 
