FUMIGATION OF NURSERY STOCK. 



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be kept on hand for the acid. With a pail of water and a tin cup the 

 equipment is complete. 



Making the Gas. 



1. Measure the acid in the glass beaker and pour it into the jar. 2, 

 Measure the water and pour this on the acid. 3. Drop in a bag of cyanide, 

 bag and all, close the door quickly, lock it, and leave the desired length of 

 time — half an hour or more, as above stated. In the meantime the 

 foreman should see that nobody enters or loiters about the house, as the 

 fumes are highly poisonous. One man should always be held responsible 

 for fumigation of nursery stock, and keep time, so that the house can be 

 opened and thoroughly ventilated later. 



There is a slight formation of steam when the water is poured on the 

 acid, but this is not dangerous. On the other hand, however, when the 

 bag of cyanide is dropped into the liquids there is a bubbling and hissing 

 similar to that produced by a piece of redhot iron in cold water. There 

 is a dense cloud of so-called steam given ofi*, which in itself is one of the 

 most deadfy, poisonous gases known to chemical science. It has an odour 

 similar to that of peach kernels. The lungs once filled with it would produce 

 instantaneous death. Therefore, do not stick your nose over a jar or in a. 

 house to test the gas. The residue in the jar should be emptied after each 

 fumigation, and a new stock made up each time. 



How TO Estimate Chemicals. 



Suppose we had a room containing 564 cubic ft., which we desired to fill 

 with nursery stock and fumigate. I have found that 0*25 (twenty-five 

 hundredths) gramme of cyanide per cubic ft. gives satisfactory results in 

 all cases. To estimate the amount of chemicals necessary for this room 

 multiply 564 by 0'25, thus: 564x0*25 = 141 grammes of cyanide. To 

 reduce this to ounces divide by 28'35, as there are 28-35 grammes in 

 an ounce, thus : 141-f-28*35 = 5 oz. (a fraction less), the amount of cyanide 

 needed for this house. 



My rule is to use a half more acid, liquid measure, than cyanide, and 

 a half more water than acid. For this room we therefore needed 5 oz. 

 cyanide, by weight, 7^ oz. acid, liquid measure, and 11^ oz. water, liquid 

 measure. I discard the fractions and measure the chemicals in round 

 numbers. Any house or inclosure can be estimated by following this 

 outline rule. 



Effect of Gas on Nursery Stock. 



I made a series of tests in '99, and determined the physiological effect 

 upon various kinds and grades of nursery stock. I found that June 

 buds and low-grade Peach, commonly called 'Svhips," will not stand the 

 gas stronger than 0-18 gramme per cubic ft. If low-grade Peach and June 

 buds are to be fumigated the amount of cyanide used should be reduced to 

 0*16 or 0*18 gramme per cubic ft. Use the same strength for buds, grafts 

 and scions, and do not leave them exposed longer than a half- hour. 



I have found that the tender terminals of fully-matured tirst-class; 

 Peach were not injured in the least with 0*25 gr., even when they were 



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