CENTRIFUGAL NOZZLES. 
213 
what sharply into the chamber as well as into the beginning of the out- 
let passage, there will be less liability to clogging. 
While clogging seems reduced to a minimum in these nozzles, in view 
of the fact that any nozzle may be tilled with rubbish, a removable face, 
cap, or plug in combination with the rotation chamber is used for those 
of the small size, but the necessity for cleaning need not occur if proper 
attention is given to straining with devices such as are described else- 
where in this report. 
The advantage of using only a single entrance to a nozzle is easily 
seen. One large orince for the given volume of water to be thrown is 
less likely to choke than two, each of half its capacity. On this account, 
aud in order not to increase friction, more than one inlet should not or- 
dinarily be used. But, on the contrary, most of the rotation nozzles that 
have been put upon the market have at least two inlets, and Buffer from 
clogging more than twiee as much as they otherwise would. To avoid 
the same impediments it is also desirable to have the inlet or inleU as 
Rtraight as possible and eccentrically parallel to a tangent to the out 
side of the rotation cavity ; yet, a curve is not specially objectionable 
in this passage if it be in the direction of rotation, as shown in Plate 
XXVI, Fig. 4, for it then may serve rather as an auxiliary thereto. 
The best form of inlet is the straight, tangent i. illy inserted tube or pas- 
sage in the circumference of the rotation cavity, and this appears in 
most of these new rotation nozzles, as in Plates X XI V and XXV. But, 
on the contrary, every centrifugal nozzle that I have been able to lind 
in the trade depends on some objectionable form of entrance passage, 
retarding the motion, liable to choke, or with passages with difficulty 
accessible lor cleaning out. It should be remembered that a crook equiv- 
alent to a right angle, by its resistance, causes over one-third more la- 
bor at the force-pump as wasted energy, or, inversely, with the same 
power at the pump not two-thirds as much spraying power at the noz- 
zle will result. 
An entrance-tube at an angle with the axis of the chamber, but tan 
gential to the outside, gives an advantage by adapting the spray for 
sprinkling from beneath upwards or from above downwards, while it 
serves well for broadcast throwing also ; and it should be observed that 
in these nozzles which at present seem most preferable for poisoning 
cotton from beneath, the tangential entrance-tube Stands about at right 
angles to the axis of the spray. At the same time, the nozzle does not 
project upwards to any marked extent above its feed-pipe, and hence 
cannot catch upon the plants under or against which it is drawn. On 
the other hand, the long barrel-nozzles cannot be used for this purpose, 
because they form a hook or angular projection, which would hang upon 
the plants. 
Certain variations of these 1 characteristics already given will be pre. 
sented in the examples to be described further on, which show the con- 
