882 



Protecting Canal Zone Buildings with 

 an Oil Moat for Insects 



IN the Panama Canal Zone ants, lizards, 

 snakes and creeping insects are so 

 numerous and so pestiferous that it is 

 difficult to keep them from climbing up 

 foundation pillars 

 and invading houses. 

 Hence concrete gut- 

 ters are provided for 

 all posts. Of course, 

 the ants can crawl 

 up the concrete as 

 freely as they can 

 up wood, but when 

 they reach the land- 

 ing platform of the 

 gutter they find 

 a miniature lake 

 of oil-insecticide 

 awaiting them. 

 They never get be- 

 yond this little moat. 



To prevent the fre- 

 quent rains from running 

 into the insecticide, a bungalow top, also 

 of concrete, forms a sheltering roof for 

 the gutter. 



Popular Science Monthly 



Enveloping Trees in Freezers to 

 Study Temperature Effects 



A CONTRIVANCE designed to freeze 

 whole trees has been constructed at 

 the Utah Agricultural College, Logan, 

 Utah, to aid in experimental work intended 

 to discover, under actual orchard condi- 

 tions, the frost danger point. 



The contrivance is very similar in princi- 



GALVAN12E0 IRON" 

 TANK 



5ELF REGISTERING 

 THERMOMETER 



-INNER WALE, 



pie to the old fashioned ice-cream freezer. 

 It consists of a huge galvanized iron tank, 

 large enough to enclose an entire tree. 

 This tank is divided into halves and each 

 half is fastened to a plank base, so con- 

 structed that a half can be placed on 

 either side of the tree to be frozen, and the 

 two parts drawn to- 

 gether, completely 

 enclosing the tree. ' 

 The tank is 

 double walled, with 

 a four-inch space 

 between the walls. 

 A large lid covers 

 the tank and rests on 

 the inner wall. Ice 

 and salt are packed 

 in between the walls 

 and over the lid. 

 The temperature in- 

 side is regulated by 

 pumping in cold or 

 warm air, and the 

 air inside is kept 

 stirred by an elec- 

 trically driven fan. Four self-registering 

 Weather Bureau thermometers and a ther- 

 mograph, hung from different branches of 

 the tree, keep an accurate record of the 

 temperature within the tank. 



The resistance of buds to frost can be 

 accurately determined by this method 

 and data collected that will tell when 

 smudge pots or other artificial means of 

 orchard heating should be used to save 

 the fruit crop. , 



The tree is not injured by the process, 

 since care is taken and constant watch is 

 kept to prevent the danger point from 

 being reached. 



The insecti- 

 cide in the 

 gutter is pro- 

 tected from 

 rain by a 

 cement roof 



AIR STIRRED 6Y 

 ELECTRIC FAN 



OnrlDESD PLAJIK BASH 



The tank is double-walled, with a four-inch 

 space between walls. In this space snow 

 and ice are packed just as in a cream freezer 



Each of the two sections of the tank cd 



to a plank base. These are drawn together 

 and a large lid covers both halves when joined 



