205 



strongly of the opinion that when a tent of this color is used the foliage 

 of the trees will be injured less when by inadvertence an overdose of 

 the materials has been used than would be the case if a light-colored 

 tent were to be used ; the light rays, more than the rays of heat, serve 

 to decompose the gas, and on this account any medium that will inter- 

 cept the rays of light will, in a great measure, prevent the decomposing 

 of the gas. In all cases where a blower was used for distributing the 

 gas inside of the tent, the gas entered the blower direct from the gen- 

 erator and was forced into the lower part of the tent through a tin pipe, 

 and the pipe which conducted the air and gas from the tent to the blower 

 also entered the lower part of the tent and then turned upward, termi- 

 nating near the top of the tent. By this means the gas and air in the 

 upper part of the tent were drawn out and after passing through the 

 blower again entered the lower part of the tent. This was for the pur- 

 pose of more thoroughly circulating the gas inside of the tent; but, as 

 will be seen by the later experiments this arrangement was found to be 

 entirely unnecessary when the generator was placed under the tent* 

 In nearly all of the later experiments too large a quantity of the ma- 

 terials was used, resulting in more or less injury to the tree or fruit, 

 the injury being always the most severe on the topmost portion of the 

 tree. The cyanide solution used in a few of these experiments con- 

 sisted of 5 pounds of cyanide dissolved in 1 gallon of water, each fluid 

 ounce of the solution containing an ounce by- weight of the cyanide. 

 The diluted sulphuric acid was composed of two fluid parts of the acid 

 and three of water, and was allowed to become cold before being used. 



(205) Took 10 fluid ounces of the cyanide solution and added in 

 three minutes 12 fluid ounces of the diluted acid. 12.30 to 12.45 p. m., 

 September 23, sun shining, light breeze. Scarcely turned the blower 

 at all. Tree 12 feet high by 10 in diameter. When the tent was re- 

 moved about half a dozen leaves on the new growth had perceptibly 

 wilted. October 19, about three dozen leaves were dead ; found eight 

 live red scales, equally distributed on the leaves and fruit. 



(206) Took 4 fluid ounces of the cyanide solution, and added in a 

 minute and a half 2J fluid ounces of pure sulphuric acid ; turned the 

 blower three minutes after adding the acid. 1.10 to 1.25 p. m., Sep- 

 tember 23, sun shining, light breeze. Tree 7 feet tall by 6 in diameter. 

 When the tent was removed several of the leaves had wilted. Octo- 

 ber 19, about three dozen leaves and a large portion of the twigs on 

 which they grew were dead ; found only one live red scale, which was 

 located upon a leaf. 



(207) Took 6 ounces by weight of the dry cyanide and added in four 

 minutes 12 fluid ounces pure sulphuric acid ; turned the blower live 

 minutes. 3.10 to 3.30 p. m., September 23, sun shining, light breeze. 

 Tree 10 feet tall by 7 in diameter. October 19 ,leaves and fruit unin- 

 jured ; found four live red scales, all of them located upon the leaves. 



(208) Took 7 ounces dry cyanide and added in four minutes 16 fluid 



