20 AGRICULTURAL CHEMISTRY 



in bending glass tubes. Number 24, Plate II, is an iron 

 ring-stand with three rings, and No. 25 is a single clamp. 

 The iron stand with rings is used for supporting appara- 

 tus, particularly the sand-bath (19) in which is a thin 

 layer of sand. The evaporating dish (5), beaker (12), 

 and flask (26) are all supported in the various experi- 

 ments upon the sand-bath and iron ring- stand. In the 

 cutting of glass tubes and the perforation of corks, the 

 two files (i and 2) are employed. Test-tube (13) is used 

 extensively in the laboratory, and when heated it is sup- 

 ported in the test-tube clamp ( 18). This test-tube clamp 

 is held in the hand. The test-tube is cleaned with the 

 test-tube brush (17) and when not in use is placed in the 

 test-tube rack (14). When solutions are filtered, the 

 funnel (15) is used, and is supported in the wooden 

 stand (21). Substances are pulverized or mixed in the 

 mortar (16) which is supplied with a pestle. The vari- 

 ous gases, as oxygen, hydrogen, and nitrogen, are col- 

 lected in the small cylinder (10), and in some of the ex- 

 periments, the large cylinder (n) is used. The iron 

 spoon (8) is used for the ignition of substances. The 

 crucible tongs (3) are for handling pieces of apparatus 

 when hot. The other pieces of apparatus, Woulff bottle 

 (7), water-bath (4), tripod (22), Hessian crucible (20), 

 wide-mouthed bottle, (9), and the ground glass plate 

 with a hole, are used in various ways in the different ex- 

 periments. Glass rods, a thistle-tube, a pneumatic trough, 

 and small squares of plain glass complete the set of appa- 

 ratus. A few pieces, used only occasionally, are obtained 

 from the instructor at the time the experiments are per- 

 formed. 



