CHEMICAL FARMING 229 



ing therefrom an oily residue, quite detrimental 

 to plant growth. Hot "chunk" tar works well and 

 makes a satisfactory, water-tight tank. Cement 

 tanks give an alkaline reaction, to counteract 

 which, a dilute solution of sulphuric acid may be 

 used. As some plants require an alkaline reaction 

 and others acid, the conditioning of chemical farm- 

 ing must be carefully attended to. In this, experi- 

 ence is almost the only teacher. 



Since beginning my experiments with culture 

 without soil, and showing in my lectures pictures 

 illustrative of the method, Paramount also showing 

 a story in their News Reel, and several articles hav- 

 ing been published, I have been deluged with re- 

 quests for the formula and instructions, until my 

 daily mail must rival in volume that of the most 

 glamorous movie star and I find it impossible to 

 answer them. This has necessitated the publishing 

 of a pamphlet with complete instructions, but even 

 this help is not adequate. Not to be put in the posi- 

 tion of withholding beneficial information as to cul- 

 ture and competent blending of the necessary in- 

 gredients of the formula, I have put up in cartons, 

 containing about four and one half ounces, enough 

 for a twenty-five gallon tank. This I can send for $ i 

 each. Although the cost of the chemicals is compara- 

 tively small, the time consumed and expense of prep- 



