1910.] PUBLIC DOCUMENT — No. 31. 215 



results were ready for publication. It is therefore desirable, 

 for the sake of placing responsibility, to state that the experi- 

 ments were planned largely by the writer, assisted to some ex- 

 tent by Mr. Tower; that the entire care of the plants, the fumi- 

 gations and the observation of the results were the work of Mr. 

 Tower ; while most of the conclusions and the duty of editing 

 the work for publication have fallen upon the writer. In fact, 

 the original work herein contained should be regarded as j\Ir. 

 Tower's, while for the planning of the experiments and the 

 editorial work the writer should be held responsible. 



Three varieties of tomato ■ — Livingston, Lorillard and Free- 

 dom — were selected, these being the ones most generally raised 

 under glass in Massachusetts. Two plants of each variety were 

 used in each test. In the tabulations which follow, factors 

 connnon to the entire set are given before the tabulation itself. 

 The abbreviations indicating the results are as follows: — 



B, burned. 



BB, badly burned. 



BC, burned and leaves curling. 

 BI, badly injured. 



C, leaves curling. 

 I, injured. 



K, killed. 



N, normal (uninjured). 



SB, slightly burned. 



SI, slightl}' injured. 



TI, temporarily injured. 



TK, top killed. 



VBl, very badly injured. 



Wilted leaves are the first indication of injury. If this is 

 not too severe they gradually become normal again. Curled 

 leaves indicate more serious effects, but plants thus affected fre- 

 quently become normal later. 



The fumigation in all cases was with 98 per cent, to 99 per 

 cent, potassic cyanide, the proportions of the cyanide, acid and 

 water used being 1, 2, 4. The column marked " Time of ex- 

 posure " gives the time at which the treatment began. Temper- 

 atures are given by the Fahrenheit scale. 



The first two sets of experiments were carried on in direct 

 sunlight. In the first set periods of ten, twenty, thirty, forty- 

 five minutes' and one hour's exposure quickly showed that it was 

 not necessary to make any long exposures with the greater 

 strength of cyanide, and, accordingly, exposures of ten, twenty 

 and thirty minutes only were made, even the shortest of these 

 being too severe a treatment for the plants. 



