The Cabbage Root Maggot. 533 



liquid was applied and the other was left untreated. No flies ever emerged 

 in the treated cage, while nearly every one of the puparia gave out a fly in 

 the untreated cage. In nd case did the plants show any signs of injury 

 from the liquid. We always applied the liquid in a horizontal hole begin- 

 about three or four inches from the plant and running down to a point a 

 little below the roots. . 



But while our experiments demonstrated that the substance 

 was sure death to the insects and did not injure the plants, we 

 were convinced that to make the method practicable in the field, 

 some method must be devised by which the liquid could be more 

 quickly, safely and perhaps efficiently applied. 



It seemed as though some instrument might be, or possibly 

 had already been, devised by which the liquid could be thus 

 applied. We were unable to find any record of such an instru- 

 ment having been devised in this country. The " Pal-injecteur " 

 used in France is also too extremely heavy and clumsy, and 

 very expensive. 



The instrument devised by Prof. Cook in 1884, for the under- 

 ground application of kerosene emulsion, apparently could not be 

 adapted for the use of the bisulphide of carbon. Mr. Barnard's 

 " Nether-inserter, " devised in 1883, facilitated the making of the 

 hole, but not the application of the liquid. Thus no instrument 

 seemed to have been devised by which the application of the 

 liquid could be made practicable in cabbage or cauliflower fields. 



The case was stated to Mr. McGowen, the inventor of the 

 famous McGowen Spray Nozzle. After several experiments in 

 trying to simplify the French instrument, the idea was abandoned. 

 He then started out on a theory of his own, and finally devised 

 an instrument which seems to "fill the bill" quite completely. 

 In honor of the inventor, we shall call it " The McGowen In- 

 jector." In construction, it is very simple, as the sectional 

 drawings in fig. 17 show; the description of the different parts, 

 and how they work are given below. 



Description of the McGowen Injector. — Figure it,B, represents a sec- 

 tional view of the instrument, about one-seventh natural size. It consists of 

 a long piston,/, its upp^r portion working closely in a small cylinder; the 

 middle portion passing through the long reservoir, r ; and to the lower 

 smaller portion which passes through that part of the instrument, g, which 

 is forced into the ground, is attached the valves, v, working in a cylinder at 

 tachcd to the lower end of the reservoir. A handle is attached to the upper 



