EFFECT OF X-RAYS ON TRIBOLIUM CONFUSUM 



581 



ages used. The tube was connected to the transformer by | 

 inch rods, to prevent corona. Where these rods entered the 

 lead box, the lead was replaced by lead glass 1 inch thick, which 

 acted both as insulation and as X-ray protection. 



A chamber of lead {A, fig. 1) 7 cm. square and 5 cm. long 

 was placed in the wall of this lead box, directly opposite the focal 

 spot of the X-ray tube. A sheet of aluminum 0.025 mm. thick 

 was fastened across the end of the chamber nearest the X-ray 

 tube. This protected the interior of the chamber from electro- 

 static effects, and prevented any NO2, ozone, etc., from the in- 



^^727 ■ 



Fig. 1 Diagram of apparatus 



terior of the lead box, and any radiant heat from the X-ray tube 

 from entering the chamber. The lead sides of the chamber 

 protected the interior from any secondary X-rays which might 

 be produced on the walls of the lead box. The only rays which 

 could enter the chamber were those sent out directly from the 

 X-ray tube itself. 



Into this chamber were placed, four at a time, the boxes of 

 beetles to be rayed. These boxes were of wood, cylindrical in 

 shape, 1| inches in diameter and f of an inch high. The wood 

 was I of an inch thick. Each box contained 25 beetles and a 



