204 PURIFICATION OF AIR 



ideas, of the deleterious effects of this air 

 on animal life, too far ; for no mischief has 

 ever happened, as far as common experience 

 goes, to persons sleeping in apple or olive 

 chambers, neither do the inhabitants of the 

 confined huts in Covent-garden market appa- 

 rently suffer, from living day and night 

 among heaps of drying herbs. Mischiefs 

 have unquestionably arisen from flowers in 

 a bed-room, or any other confined apartment, 

 but that is to be attributed to their perfumed 

 effluvia. So the bad effects, observed by 

 Jacquin, of Lobelia longiflora on the air of a 

 hot-house, the danger incurred by those who 

 sleep under the Manchineel-tree, Hippomanc 

 Mancinella^ or, as it is commonly believed, 

 under a Walnut-tree, are probably to be at- 

 tributed as much to poisonous secretions as 

 to the air those plants evolve. 



Dr. Ingenhousz introduced leaves into glass 

 jars filled with water, which he inverted in a 

 tub of the same water, and placed the whole 

 together in the sun-shine. From their under 

 sides came streams or bubbles of air, which 

 collected in the inverted bottom of each jar. 

 The air thus procured proved oxygen gas, 



