FUMIGATIOlSr OF ORNAMENTAL GREENHOUSE PLANTS. 3 



with straight sides are frequently sold with glazed earthenware tops. 

 These tops or covers increase the cost of the generators and, further- 

 more, are useless for fumigation purposes. Therefore, when genera- 

 tors are ordered it should be indicated that tops are not desired. 

 With this type of generator a cover may be improvised by using a 

 piece of corrugated galvanized iron roofing or a board with cleats on 

 the underside, to allow the free exit of gas, 



MISCELLANEOUS REQUIREMENTS. 



Correct scales or balances, reading in tenths of an ounce, are con- 

 venient for accurate work. An 8-ounce graduate is desirable for 

 measuring the acid and water. To avoid splashing of the acid it 

 should not be poured from a carboy or bottle into the graduate but 

 should be transferred to a porcelain pitcher, from which it may be 

 poured with safety. It is well to have on hand a supply of small 

 bags or tissue paper in which to place the cyanid. 



PREPARATION OF HOUSE FOR FUMIGATION. 



As a preliminary to fumigating the house it is essential that the 

 exposed glass surface be examined carefully and all broken glass re- 

 placed. All cracks should be thoroughly closed. The ventilators. 



Fig. 2. — Methods of attaching rod and cord (a, h) to ventilator shaft of greenhouse so 

 that the ventilators can be opened from the outside ^fter fumigation. (Original.) 



both side and top, where possible, should be so arrange^ that they 

 can be opened on the outside of the house upon the completion of the 

 exposure. This can be accomplished by disconnecting the " machine," 

 or gear, of the top ventilators and attaching to the central ventilator 

 shaft (see fig. 2) an arm (a or h) which can be controlled by a cord 

 or wire which extends through the side of the house. The gears on 

 the side ventilators may be disconnected so that the sash may be 

 opened from the outside. If only one ventilator can be opened it is 

 preferable that it be the one on the roof of the house. 



