34 



PLANT PHYSIOLOGY. 



Carbon dioxide generator, of usual simplest chemical form (Fig. 7), 



Scissors and shears ; scalpels. 



Rubber stamp, marking small squares, and ink-pad (see page 106). 



Bicycle-pump (preferably a foot-pump, costing 50 cents). 



Spirit-level, 12 to 15 cm. long. Very valuable for some purposes, such 

 as truing the cylinders of recording mechanisms (page 105), is a piece of 

 slate 2 cm. thick and 30 cm. square, set on three levelling-screws. 



Supply of porous flower-pots of different sizes. 



Supply of glass tubing of the various smaller sizes, principally i mm, 

 thick and 3, 5, and 7 mm. bore ; also some capillary tubing. 



Supply of rubber tubing of the different smaller sizes, principally 4, 

 8, 12, 1 6 mm. internal diameter, of soft black rubber, and some of the 



o 



FIG. 7. RECEPTACLES FOR CHEMICALS, ETC. 



In the center, mercury reservoir ; below, pressure manometer ; on the left, 

 aspirator bottle; on the right, phosphorus -carriers and carbon dioxide generator* 

 All i true size. 



thick cloth-wrapped kind used for gas conduction, also one meter of the 

 smallest obtainable. 



Supply of rubber stoppers; most useful sizes are 20, 24, 28, 32 mm. 

 diameter at large end ; also some with two holes (which can be stopped 

 with sealed glass tubing if not needed). 



Supply of good quality ordinary corks, different sizes. 



Set of 10 cork borers, with sharpener, and a cork-presser. 



Spools of copper wire of sizes 16 and 20, kept hanging over the tool- 

 table. Also a spool of the finest wire ; also some No. 20 elastic iron or 

 brass wire. 



Electrician's tape or tire-tape, large roll. 



