704 Journal of Agricultural Research vol. vi, no. 18 



fruit sufficient for experimental purposes when stored in it under condi- 

 tions approximating those of commercial practice, or otherwise, as de- 

 sired. For example, a large bunch of bananas may be suspended in it 

 from a removable cross of iron pipe the ends of which rest upon cleats 

 fastened in the corners of the chamber near the top. Other cleats at 

 different levels provide supports for shelves or for trays, baskets, or other 

 containers in which the experimental material may be placed. 



The walls of the chamber, which are of sheet copper 0.5 mm. thick, are 

 attached to the inner side of a framework of hard-maple strips, experi- 

 ence having shown that using wood in place of metal lessens the possibility 

 of error. The vertical strip in each corner of the frame is 3 cm. square, 

 with the inner corner cut away on each side to a depth of 5 mm. to form 

 a recess for the corner of the copper walls. At the top and bottom of 

 the chamber, and midway between, the ends of cross strips 25 mm. 

 square are joined to the posts so as to form a rigid supporting structure 

 which is strong, though consisting of but little material. At the lower 

 end each post extends 4 cm. below the bottom cross strip, to provide a 

 leg for the structure. Elbows of stiff sheet copper, with one branch 

 soldered to the outer surface of the copper wall and the other screwed to 

 the framework, hold the copper firmly in place against the wooden frame. 



At the top of the chamber is a close-fitting removable cover (PI. XCII1) 

 of sheet copper on a maple frame, with the metal projecting in a rim to 

 hold the cover in place. The edge of the rim is bent down to fit into a 

 groove in the flange formed by extending the copper side walls at the top 

 to the outer edge of the maple frame. Wax melted into the groove seals 

 the joint between the top and side walls when the cover is in place. 



In the middle of the upper half of each of two opposite sides of the cham- 

 ber is a framed opening 13 by 18 cm., forming a recess in which a pane of 

 glass may be sealed (PI. XCIII). These windows afford a view of the 

 contents of the chamber and opportunity to watch the changes taking 

 place. They may also be arranged so that either one may be opened 

 during an experiment to remove a sample of the material under observa- 

 tion, if desired. 



Another wall has a circular opening framed with a tube 9.5 cm. in 

 diameter, in which is fitted a device called an "outlet" (see PI. XCIII) 

 which provides apertures for pipes conducting a ventilating current of air 

 into and out of the chamber, for resistance thermometers providing pas- 

 sage for water entering and leaving the heat absorbers, for wires leading 

 to electric- resistance thermometers inside the chamber, and for other 

 purposes, as needed, all of which may be sealed in place. All openings 

 into the chamber other than the windows are thus brought together in 

 the one device, which is easily separated from the chamber so that the 

 latter may be removed and another of different capacity substituted for 

 it. During an experiment every joint in the chamber is air-tight. 



