May 



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SCIENCE 



395 



run through the powder-chamber, keeping the powder constantly 

 stirred up ; and, no matter in what position it is held, the same 

 regular supply is blown out. A detachable spout enables the oper- 

 ator to blow up under the foliage of vines and potatoes without 

 stooping and getting into tiresome positions. 



For applying fluids, there is an ingenious device nearly ready to 

 be put on the market, which looks not unlike a Babcock fire-extin- 

 guisher. It is carried on the back of the operator, which enables 

 him to carry twice the quantity of fluid with greater ease than by 

 the old method, with a bucket. But its great merit lies in the fact 

 that the fluid is forced out by compressed air, through two short 

 pieces of hose, which are held in each hand, enabling two rows to 

 be easily covered at a fair walk. The fluid can be applied in the 

 form of mist, spray, or stream, at will ; and, when the air has been 

 exhausted, a few movements of the small pump-handle are sufficient 

 to recharge it. Vaporizing-bellows are also exceedingly valuable 

 •for applying solutions of alcohol, kerosene, fir-tree oil, and other 

 insecticide solutions of like character, which are such thorough 

 insect-exterminators, but so dangerous to the plant when carelessly 

 applied by syringe or sprinkler. With the vaporizing-bellows, 

 these strong fluids can be applied almost like vapor, and the insects 

 are killed without danger to the plants. Some of the newer spray- 

 ing-pumps for orchard and field use are a step in the right direc- 

 tion. A " return discharge " is added, the mouth of which can be 

 placed near the suction-pipe at the bottom of the barrel ; and it 

 keeps the solution thoroughly churned and mixed, as no stirring with 

 a stick can do. When kerosene emulsion, fir-tree oil, or other oily 

 insecticide is used, which rises naturally to the surface, the mouth of 

 the return discharge should be placed on or over the surface. 

 Kerosene, when intelligently applied, is a valuable remedy. We 

 know of its being used, to the exclusion of all other insecticides, in 

 greenhouses containing the rarest plants ; and brighter, cleaner, 

 healthier stock we never saw. But it is used with discretion. On 

 woody and hardier plants, such as camellias, palms, azaleas, etc., 

 one pint of kerosene to four gallons of water is used ; and for deli- 

 cate-foliaged plants, from one-third to one-half less kerosene is 

 used. When applying the solution, one man is constantly drawing 

 and forcing the fluid back through a syringe into the bucket, while 

 another fills his syringe with the thoroughly churned solution, and 

 applies it to the plants : therefore these return-discharge pumps are 

 gotten up to work on the same correct principle as that of the two 

 men just described, for applying not only kerosene, but London 

 purple and Paris green poisoned waters as well ; for these two 

 powders are not soluble, and soon settle to the bottom, leaving the 

 surface water too weak, and that at the bottom so strong that the 

 foliage is likely to be injured. 



Insect-killing powders are much more efficacious when blown 

 into the plant than when dusted on, as is the usual practice. When 

 blown on with a bellows or other implement, the powder separates 

 into clouds of impalpable dust ; and the force causes it to pene- 

 trate the innermost crevices, destroying the hidden insects and 

 larvffi by filling their breathing-pores (which, as all know, are situ- 

 ated in rows on each side of their bodies), thus suffocating them. 

 This is the main reason why non-poisonous powders are frequently 

 as effectual as poisonous. We know of a firm of large cabbage- 

 growers in Florida who have saved their crops for several years, 

 while their neighbors' have been almost a total loss, simply by blow- 

 ing Persian insect-powder of high grade into each plant with a 

 finely-distributing bellows. Their men go over the fields occa- 

 sionally, not stopping to see whether a cabbage is affected or not, 

 and simply puff a small quantity of powder into each in a rapid, 

 business-like manner ; and the result speaks for itself. You will 

 notice that we emphasize " high grade " in connection with the 

 Persian powder. We do so, because the cheap grades are almost 

 worthless. The " high grade infallible " is produced from the half- 

 opened flowers and buds of Pyrethrum rosi-iiin or its hybrids, that 

 from the collected wild flowers being superior to the cultivated ; 

 while the cheaper grade is made from opened flowers gathered 

 later in the season, with frequently the flower-stems ground in ; 

 and lots of useless cheap stuff is sold which is made from the stalks 

 and stems of the plant, ground and colored so finely that to the 

 uninitiated it appears better than the superior grades. The insect- 

 -destroying properties of the Persian powder depend largely on the 



fineness to which it is ground, enabling it to penetrate the breath- 

 ing-pores of the insect, and on its resinous properties causing it to 

 adhere and suffocate them. This resinous property is easily in- 

 jured by exposure, and generally entirely destroyed by dampness. 

 Dalmatian powder and buhach are made from the same family, 

 grown in other sections of the world, the former being from Dal- 

 matia, and the latter from California. All are equally good if the 

 flowers are gathered at the proper stage and thoroughly ground. 

 Persian powder has been considered superior, simply because it 

 was formerly made under the supervision of the Hungarian Gov- 

 ernment, who exacted purity and other conditions which insured a 

 high grade, which gave the powder its reputation. The pyrethrum 



LEGGETT S POWDER GL\ 1\ UIERAIIOV 



grown in California has been proved to be equally as efficacious, 

 when correctly prepared, as that from the Caucasian Mountains ; 

 the climatic conditions of the latter having no superior influence, 

 as is generally supposed. 



In poisonous powders, London purple is rapidly taking the lead. 

 It is largely used in the public parks and in government experi- 

 mental farms, and is considered superior to Paris green on account 

 of being more soluble, there being less danger of burning the foli- 

 age with it. It is said to go further, and is certainly much cheaper, 

 which is accounted for by its being a by-product. When used as 

 a powder, it also has the advantage of being more readily seen on 

 the plants. The adulterants usually mixed with it are either land- 

 plaster, road-dust, plaster-of-Paris, or cheap flour ; and it is ad- 

 visable to mix thoroughly at least twenty-four hours before use, 

 which allows the adulterant to absorb the poison, making it more 

 effectual. Where small areas only have to be gone over, flour is 

 the best, as it adheres tenaciously to the foliage, and it is more in- 

 viting to the insectivorous appetite than minerals. When mixed 

 with flour, one pound of London purple to twenty to thirty pounds 



