New York Agricultural Experiment Station. 347 



25), Savelot and Fruitall, and the Deming Century. A variation of 

 this form is found in the Hardie (Fig. 26) and the Spramotor (Fig. 

 27), in which the pump is supported in the middle of the barrel on 

 a foot piece. 



So-called double-acting pumps. — Some. hand pumps are desig- 

 nated as double-acting, meaning in this case that a part of the con- 

 tents of the cylinder is discharged through the port with the for- 

 ward stroke of the lever and the rest with the return stroke. These 

 pumps maintain a continuous and uniform discharge at the nozzles 

 with a small air chamber or even with none at all. Goulds' Standard 

 (Fig. 28) is an example. 



True double-acting pumps. — The true double-acting pump is one 

 in which a certain quantity of liquid is taken in and also a like 

 quantity discharged at both the forward and the return strokes of 

 the lever. Pumps of this type used for spraying purposes are usually 

 horizontal pumps. They are of large capacity and are generally 

 used with a tank outfit, though Brown's Siphonette is regularly used 

 also with a barrel outfit. They of course require more expenditure 

 of power than do single acting pumps of the same cylinder dimen- 

 sions. Goulds' Sentinel Jr., Douglas' horizontal double-acting, the 

 Friend, Brown's Siphonette (Fig. 29) and Deming's Planet (Fig, 

 31) are examples of this class. 



Tivo-cylinder pumps. — A two-cylinder pump is described by its 

 name. It consists of two independent cylinders operated by a com- 

 mon lever. These pumps have great capacity and are used on tank 

 outfits. To this class belong Goulds' Monarch (Fig. 32), Brown's 

 Hydraplex and the Friend Horizontal (Fig. 33). 



Rotary or " clock " pumps. — The rotary or clock pump is theo- 

 retically one of the best adapted to spraying purposes, but practically 

 quite otherwise. These pumps have good capacity and are easier 

 of operation than others here mentioned, but from the nature of 

 their operation, which is that of two metal surfaces in contact with 

 each other, they are short-lived. These working parts are made of 

 brass and this soft metal is very soon worn. A pump of this type 

 is shown in Fig. 30. 



