4-88 Plant Case for growing Plants 



Before entering on this investigation, it may not, however, be 

 out of place to advert to the origin of the invention which has 

 just been described. From his early youth, Mr. Ward had been 

 attached to botanical pursuits ; but, living in a situation enveloped 

 in the smoke of numerous manufactories, he had been compelled 

 to give up the cultivation of plants, after many unavailing trials. 

 At length, a simple incident put him on new experiments, and 

 led him gradually to the results we are about to detail. He had 

 buried the chrysalis of a sphinx in some moist mould, which was 

 contained in a wide-mouthed glass bottle, covered with a lid. In 

 watching the bottle from day to day, he observed that the mois- 

 ture, which, during the heat of the day, rose from the mould, 

 became condensed on the inner surface of the glass, and again fell 

 back to the mould, so as to keep it always in a state equally moist. 

 About a week prior to the final change of the insect, a seedling 

 fern and grass appeared on the surface of the mould. After 

 having secured the insect, Mr. Ward set himself to watch the 

 developement of these plants in such a confined situation. He 

 placed the bottle on the outside- of the window of his study, 

 where the plants continued to grow, and turned out to be the 

 Poa. annua, and Nephrodium i^ilix-mas. From this incident, 

 so well improved by Mr. Ward, have arisen the results, both 

 physiological and practical, which form the subject of the present 

 communication. These results were published in the Companion 

 to the Botanical Magazine, edited by Sir W. J. Hooker, in May, 

 1836; but the incident which gave rise to them, and the experi- 

 ments to which it led, occurred seven or eight years before, 

 that is, about eleven years from the present time (1839). 



His previous want of success in growing plants in the ordinary 

 mode, Mr. Ward attributes to the "depressing influence of the 

 fuliginous matter with which the atmosphere in which he lives is 

 impregnated." The real mode, however, in which such an 

 atmosphere proves injurious to vegetation, was first shown by 

 the experiments of Doctors Turner and Christison, which were 

 published in the 93d number of the Edinburgh Medical and 

 Surgical Journal. They ascertained that it is not simply to the 

 diffusion of fuliginous matter through the air, but to the presence 

 of sulphurous acid gas, generated in the combustion of coal, that 

 the mischief is to be ascribed. When added to common air, 

 in the proportion of g-^Q or T ^yy part, that gas sensibly 

 affected the leaves of growing plants in ten or twelve hours, and 

 killed them in forty-eight hours, or less. The effects of hydro- 

 chloric, or muriatic acid, gas were still more powerful, it being 

 found that the tenth part of a cubic inch, in 20,000 volumes of 

 air, manifested its action in a few hours, and entirely destroyed 

 the plant in two days. Both these gases acted on the leaves, 

 affecting, more or less, their colour, and withering and crisping 



