RURAL ENGINEERING. 589 



account wliotlior the notch has a froc outfall, vclncity of a]i])n)ach, etc., and 

 examples are jriven illustrating their application. 



Triennial revenue report of the public works department, irrigation 

 branch, Bengal, for the three years ending 1904-1905 (Tricii. Rcr. Rpt. 

 Pub. WorkH Dcpt., Irriy. Brunch, liviujal, J90'i-'>, pii. .9'/, dgmx. 7). — Statistics 

 relating to the cost, operating expenses, and revenues of the canals of Bengal. 

 Figures are also given of areas irrigated, crops grown, and duty of water on rice 

 and other crops, together with items of interest on administration and control. 



Silting operations {fun jab IrrUj. Branch I'apcrx, Jo. '>, pp. J/S, pis. Id, 

 fl(j. 1). — A description of methods of strengthening the banks of a canal when 

 the bed is out of the soil or but little within it. chiefly by means of large sub- 

 sidiary basins parallel to the canal through which all or a portion of the water 

 of the canal is caused to flow, resulting in tlie deposition of silt in such basins 

 up to the usual water level of the canal. 



How horizontal runs affect the air lift, II. T. Arrams {Municipal Ewjin., 

 31 (1906), yo. .'/. pp. 2!)7, 298). — A discussion of the results of experiments made 

 by the writer upon a well operated by the air lift, where after leaving the well 

 the water bad to I)e conducted some distance by a horizontal pipe and then 

 elevated into a reservoir. It was found that the horizontal run greatly impaired 

 the action of the air lift and that it is much more economical under such con- 

 ditions to raise the water by the air lift to a tank at the surface, after which the 

 water may be forced by an air pressure or disi)lacement pump through the 

 horizontal run to the elevated tank. 



Air-lift pumping, G. ('. 11. Friedrich (Compressed Air, 11 (1900). yo. 6, 

 pp. .'fVfO, .'fl-'il). — A discussion of this method of pumping and giving tables on 

 submergence and efficiency ; capacity and pipe sizes; and on the relation between 

 lift, .submergence, and air needed for air-lift pumping. 



Tests of a new centrifugal pump (Engin. Rec, 5'f (1906), Xo. 13, pp. 

 So2, 353, /ii/s. .')). — A report of tests made upon a 2-stage shrouded runner cen- 

 trifugal pump of such design that it may readily be taken apart for inspection 

 of the interior without disconnection of the suction or discharge pipes, or may 

 be made into a simple pump or cn.e of any number of stages by mere removal 

 or addition of i)arts. In the form tested an efficiency of 77.7!) per cent was 

 shown at tUKt revolutions ])ev minute when delivering 3,255 gal. per minute at 

 100.7-ft. head. 



On the uses of the centrifugal pump (Masch. Ztf/., Jf (1906), Xo. 16, p. 

 189). — In an article by Grambei'g in Brcnnkohlc. the author mentions a tech- 

 nical but rather important consideration in the operation of the centrifugal 

 pump when same is run by electric motor. "The pressure head against which 

 the i)un)p works is often less than that for which it is designed, and in this 

 case it is found that the motor overheats on long runs, due to excessive current 

 consumption following from the reduction of head. It is a singular fact that 

 a reduction of ])ressure he.ad should result in an increased jxiwer consumption, 

 but such is the case. This is due to the fact that reduction of pressure head 

 causes increase in discharge, the net result being increase in current required. 

 To obviate this loss pumps which are designed for a higher head can lie in- 

 creased in efficiency. by placing a valve in the discharge pipe near the pump. By 

 this means it is possible to produce a throttling effect, increasing the pressure 

 and thereby reducing the discharge, and in turn cutting down the current 

 consumittion." 



Wind power, E. L. Rurxe (Gassier' h May.. 30 (1906), .A'o. .'/. pp. 325- 

 336, fli/s. 10). — The writer discusses the various types of wind wheels and 



20915— No. 6—07 m 7 



