BOLL WEEVIL CONTROL BY USE OF POISON. 21 



worked together as ' a group if some kind of torch or contractor's 

 flare is placed at the row ends to provide light. 



Another way of reducing the amount of labor involved in hand 

 dusting is by the operation of the machine from muleback. This 

 has been tried on numerous occasions and is generally much more 

 satisfactory than by walking. 



POWER DUSTERS. 



The earliest work on weevil poisoning was conducted entirely 

 with hand guns, as very small areas were treated during the strictly 

 plat-test stage of the work. Ordinarily the next step in develop- 

 ment of dusting machinery would have been to produce something 

 of slightly larger capacity, but owing to the rapid development of 

 the work at this stage, attention was transferred from the develop- 

 ment of hand guns to that of blowers of the largest possible capacity, 

 namely, the engine-power machines. In this case the duster was a 

 horse-drawn machine with the fan and feeder operated by a small 

 gasoline engine mounted on the platform. This machine had a dis- 

 tributor extending across the rear end with five nozzles spaced 4J 

 feet apart, thus covering approximately five rows. Several models 

 of these machines were devised and placed on the market and were 

 used rather extensively during 1918 and 1919. It was found that 

 they would cover from 6 to 10 acres an hour while in operation but 

 that the loss of time due to mechanical difficulties was so great that 

 a machine seldom averaged over 40 or 50 acres for the day's opera- 

 tions. Continued use of these machines soon made it obvious that 

 they were too complicated and cumbersome to be thoroughly satis- 

 factory for cotton-dusting work. Probably the most serious diffi- 

 culty was the gasoline engine. Another great difficulty was found 

 in constructing a thoroughly satisfactory distributing system for 

 spanning five rows. There was considerable length of pipe extend- 

 ing out beyond the machine on both sides and as this was necessarily 

 made very heavy, the weight caused almost constant breakage due 

 to excessive vibrations and jarring. In many cases the distributors 

 of these power dusters were cut off so as to cover only three rows 

 at a time and they really treated more acreage throughout the 

 season than when they were arranged to span five rows, owing to 

 the greater convenience in handling the machine over the field, 

 around stumps, fences, etc., and the decreased loss of time from 

 breakage. 



These power machines were placed on the market at prices ranging 

 from $400 to $600 and this price seemed high for the work they 

 could accomplish. Consequently it was desirable to devise a machine 

 which would eliminate the gasoline engine and span only three rows 



