BiGELow] PLANTS WITHOUT SOIL 73 



these over the old method with powders and mysterious mixtures, 

 the suggestion came to mind — Why not put up those nutrient 

 chemicals in tablets ? I at once gave an order to a manufacturing 

 chemist for 10,000 compressed tablets. This was in the early part 

 of 1900. All that spring and summer I experimented with my 

 tablets, as did a few teachers of botany to whom I gave a supply. 

 We used the entire 10,000. They were found to work marvel- 

 lously well, even beyond my fondest hope. The first public an- 

 nouncement was on page 557 of " Nature and Science " of St. 

 Nicholas for April, 1901, in a series of prizes offered to the young 

 folks for germinating seeds. The result of that contest, during 

 the summer and autumn of 1901, was astonishing. The children 

 made use of the tablets most successfully in growing plants in all 

 sorts of ingenious situations. I was deluged with letters from 

 young folks, teachers and parents, describing experiments. Sev- 

 eral of these letters and a number of illustrations were published 

 during the following spring in St. Nicholas (April, 1902). Later 

 accounts were given in School Science, Chicago ; and Popular 

 Educator, Boston. 



Each of the tablets is composed of the following : Common table 

 salt (sodium chloride), 2^ grains ; plaster of Paris — gypsum (cal- 

 cium sulphate), 2^ grains; Epsom salts (magnesium sulphate) ; 

 phosphate of lime, nearly the same as burned bones (calcium 

 phosphate), 2i/^ grains; East Indian saltpetre — nitre (potassium 

 nitrate), 5 grains; compounds of iron and chlorine (ferric chlo- 

 ride), nearly ^^ grain. To make the food solution, two of these 

 tablets are required for each pint (500 ccm. nearly) of water. 

 Crush the tablets to be used and put the powder in the water. 

 Shake or stir thoroughly before using. Keep the plants thor- 

 oughly moistened with this solution, which is both drink and 

 food for them. 



The solution prepared from the tablets will nourish a plant if 

 the roots can be kept supplied with it, even on top of a stone, or a 

 brick, between two sheets of glass (see Fig. 4), on crushed rock 

 (see Fig. 2), sawdust (see Fig. i), pebbles, bits of glass, or any 

 similar insoluble substance. Plants thrive well on perforated cloth 

 or wire-netting stretched tightly across any receptacle that is 

 kept filled with the solution (see Fig. 3). The photographs pub- 

 lished in St. Nicholas and other periodicals to which I have re- 

 ferred and also the new ones accompanying this article show some 



