Water-Content of Plants 



59 



LABORATORY WORK 



Water-content. - - Determine separately the water-content of 

 any convenient twigs and fruits, or of fruits and seeds ; 

 apples and apple twigs, squash and squash seed are generally 

 available. If crude scales only are accessible, use from 50 to 

 100 grams of material ; while if very delicate scales are em- 

 ployed, 10 grams are sufficient. The process may be as follows : 



FIG. 16. A dry-heat sterilizer, serviceable also in determining water- 

 content. 



(1) weigh and record weight of vessels to be employed, prefer- 

 ably small glass, aluminium, or tin dishes ; (2) mince or break 

 up the material finely, using a quantity more or less than that 

 which is desired, into the proper vessel, weigh immediately, and 

 record ; (3) dry at from 100 to 110 C. to conxlattt weight (if a con- 

 stant temperature dry-oven is at hand, leave in this until the 



