82 



JOUKNAL OF THE ROYAL HOKTICULTURAL SOCIETY. 



Some nurser}^iien have rooms large enough to admit a wagonload of 

 trees at one time. 



In a case of this kind it is not necessary to have the slat floor, as the 

 trees are loosely packed upon the wagon, and the chemicals are placed 

 imderneath the load. Where this house is used over 2,000,000 trees are 

 fumigated annually. 



Buildings of this character have been found very useful by niu'seiy- 

 men who have them. In one instance I know of a large nurseryman who 

 uses his fumigating houses for storing Potatos during the winter. His 

 rooms are built in a corner of his packing shed, and he informs me that 

 he has no difficulty whatever in keeping Potatos perfectly in them. 



Peeparation of Trees for Fumigation. 



Trees should be dug from the nursery and loosely packed in the house, 

 either on end or flat on the floor. The chemicals are then prepared and 

 placed as near the centre of the room as possible, or on opposite sides through 

 the doors in the base, as shown at d d. The door should be closed and left 

 for at least thirty minutes ; this is the minimum limit, but thoroughly 

 dormant trees are not injured, in the least, if left an hour or longer. 

 Immediately after fumigation the house should be thoroughly ventilated 

 and the trees removed, packed for shipment or heeled in. 



The Chemicals Used. 



1. Cyanide of potassiuu). 



2. Sulphuric acid, 



3. "Water. 



The cyanide must be practically chemically pure arid guaranteed 98 to 

 99 per cent. It costs from 15r7. to 18r/. a lb., depending on quantity 

 purchased at one time. I have foitdd in my experience that the 25 -lb. 

 package is the most convenient, as it is put up in tin cans with screw 

 tops, and can be conveniently handled by most nurserymen. I find that 

 cyanide broken into lumps about the size of small hickory nuts gives the 

 best results. It can be procured in small lumps by notifying the manu- 

 facturers in advance. 



The best grade of commercial sulphuric acid, specific gravity 1*83, 

 should be procured. Acid used in the manufacture of fertilisers, commonly 

 called "chamber acid," should not be used. I have secured an excellent 

 grade at a penny a lb. by the carboy. Of course, these chemicals are 

 subject to changes in price. 



It must be borne in mind that the acid cannot be placed in vessels of 

 any kind, except those made of earthenware. I have found that an 

 ordinary pickle jar or crock, holding from 2 to 4 qts., is best adapted for 

 the chemicals. Sometimes a large snuff jar is needed in a large house. 

 The cyanide should be weighed out and WTapped in strong paper bags, and 

 kept packed in the can ready for use. A glass beaker, holding at least 

 8 oz., with the ounce mark on the side, for measuring acid and water, is 

 very necessary. This method will not admit of any guesswork, and the 

 chemicals must be prepared strictly in accordance with figures given for 

 any enclosure. A bottle with glass stopper, or a chinaware pitcher, should 



