THE POWER OF WIND MILLS. 455 



The cherry or pear slugs is a near relative of the currant saw-fly, and 

 about the time of ripe cherries and in September they are on the trees. 

 Buhach or kerosene emulsion will always kill them. Koad dust or any dry 

 earth sometimes will do so, but does not seem to be always effective. Freshly 

 slacked lime will also kill them with certainty if dusted thoroughly on the 

 trees. 



Parasites are little insects that live within other insects, and on such 

 minute beings are we more dependent in our contest with our insect enemies 

 than upon any other agency. Fifty- three million dollars injury was done to 

 the wheat of Illinois in one year by the Hessian fly. The next year the 

 wheat of Illinois was saved by the work of these little parasites. We have 

 even gone to France to import parasites to fight ingects with. 



On shade trees where leaves are eaten use arsenites. If Buhach is effective 

 use it. and where arsenites or Buhach cannot be used use the kerosene 

 emulsion. 



Question: Is the Nixon nozzle better than the Cyclone, Boss or Boston? 



Prof. Cook: I think so; it throws a finer spray, and with more force. 



Question: How would you treat insects on buds of walnut trees? 



Prof. Cook : Spray with the arsenites if the tree is not too large. 



Question: How treat the rose chafer? 



Prof. Cook: Mr. Carman says Buhach is dead shot for them. 



Question : Why is fine spray better. Is it for any other reason than 

 economy ? 



Prof. Cook : Yes ; too much poison kills the leaves. The least that you 

 can apply will kill the insects. 



Question : Will the Cyclone nozzle fit any pump? 



Prof. Cook: It can be fitted by a rubber tube to any pump. 



Question: How about the onion maggot? 



Prof. Cook : Kerosene emulsion if used early enough and persistently 

 enough will succeed. It will kill all it touches. But as they hatch every few 

 days you must use the remedy as often; and as the worms soon burrow into 

 the substance of the onion or the radish the application must be made before 

 they have got in out of reach. 



THE POWER OF WIND-MILLS. 



PROFESSOR R. C. CARPENTER. 



[From Rural New Yorker, July 30, 1887.] 



Experiments in developments of power ; power of mills overrated ; Smeaton's experi- 

 ments ; small mills proportionately less effective than large ; work of .a m,ill. 



In 1880 I spent considerable time in determining the efficiency of two wind- 

 mills. Each mill had a ten-foot wheel made of wooden slats set in the ordi- 

 nary way. One mill was new and turned very rapidly in a light wind, the 

 other was old with bearings in bad shape, and gave very poor results. The 

 following were the results of the best mill:- 



