1913] HOFFMANN—PARAFFIN BLOCKS FOR GROWING SEEDLINGS 245 
To obtain blocks of the desired thickness and size, the following 
procedure has proved most effective. The paraffin is placed with 
sufficient distilled water in a suitable vessel and boiled vigorously. 
The paraffin can then be removed from the surface of the water 
Fic. 1.—Showing use of paraffin block and hydrometer cylinder for growing 
seedlings in nutrient solutions. 
and poured into a large cylindrical mold. This mold is best made 
out of some heavy paper and can be made of any desired diameter. 
After solidification of the paraffin within this mold, the various- 
sized cylinders can be cut off in much the same manner that bread 
