310 



wood, North Carolina; wire- worms {JElater sp.) iu Washington and 

 Dauphin, Pennsylvania; grub-worms {Lachnosterna sp.) in Rockingham, 

 New Hampshire; Orange, New York; Washington and Vernon, Wiscon- 

 sin; flat-head borers iu Cloud, Kansas; slugs (?) ( ) in Kent, 

 Delaware. Forest- worms (?) destroyed apple and forest foliage in Grand 

 Isle, Vermont ; tobacco-flies {Macrosila Carolina) in Pittsylvania, Vir- 

 ginia; Hessian flies {Cecidomyia destructor) in Stone, Missouri; grass 

 army-worms [Leticania uni^nmcta) in Greene and Obion,. Tennessee; 

 in Clinton, Alexander, Randolph, Sangamon, and Monroe, Illinois; in 

 Gasconade, Howard, Saint Genevieve, Montgomery, Madison, and 

 Ballinger, Missouri. 



CHEMICAL MEMORANDA. 



By Wji. McMurtrie, CnEMisx. 



The influence of illuminating- gas upon the aerial por- 

 tions OF PLANTS. — The subject of the influence of illuminating-gas 

 upon vegetation has until within the past year or two been almost 

 wholly neglected. In 1873 some observations made in Berlin Duiu. 

 Polyt. Jour., CCVl, 345, determined the fact that gas escaping from 

 the pipes exerted an injurious influence upon the surrounding vege- 

 tation, with the roots of which it came in contact, and careful experi- 

 ment showed that this effect could be observed when so small a quan- 

 tity as 25 cubic feet per diem was distributed through 144: square feet 

 of soil to a depth of four feet. In fact, the plants whose roots per- 

 meated this quantity of soil, 57G cubic feet, were by such treatment 

 killed in a short time, and it appeared that less time was required to 

 produce this effect when the surface of the ground was closed and more 

 compact. During the same year J. Boehm, Chem. Centr., 1873, 755, 

 made some experiments by passing coal-gas through the soil of pots 

 containing varieties of fuchsia and salvia, and of the ten plants experi- 

 mented upon seven died in four months. Further experiments con- 

 vinced him of the fact that the plants were killed, not by the direct 

 action of the gas upon the roots, but by poisoning the soil. It seems, 

 therefore, pretty well established that when coal-gas permeates through 

 the soil it has' an injurious action upon the vegetation with which it 

 may come in contact. My attention has, however, been attracted to a 

 somewhat different action of the gas, which seems equally as destructive 

 as that just described. Boehm found, in the course of his investiga- 

 tion, when cuttings of willow were placed in bottles containing a small 

 quantity of water, and otherwise filled with illuminating gas, as the 

 buds developed and the leaves began to appear the latter rapidly 

 withered and died before reaching complete development. Now, this is 

 the directiqn taken in my investigation. In Boehm's paper he does not 

 state the percentage of gas in the atmosphere necessary to produce the 

 effect described, and my object was therefore, if possible, to estimate 

 the approximate quantity of gas required to bring about such results. 

 The question arose out of a dispute concerning the destruction of an 

 extensive stock of camelias in Philadelphia, in which it was alleged 

 that the loss was due to the escape of gas from the street-mains. It was 

 shown that the main was broken ; that during the winter, the ground 

 being frozen, there was no means of escape of the gas other than to 

 work its way through the subsoil, and into the atmosphere through the 

 ground of the interior of the greenhouse. The distance between the 



