344 LETTERS ON NATURAL MAGIC. 



It was discovered by Sir Humphrey Davy, that 

 this gas could be safely taken into the lungs, and 

 that it was capable of supporting respiration for a 

 few minutes. In making this experiment he was 

 surprised to find that it produced a singular 

 species of^intoxication, which he thus describes : 

 " I breathed," says he, '* three quarts of oxide 

 from and into a silk bag for more than half a 

 minute without previously closing my nose or 

 exhausting my lungs. The first inspiration caused 

 a slight degree of giddiness. This was succeeded 

 by an uncommon sense of fulness in the head, 

 accompanied with loss of distinct sensation and 

 voluntary power, a feeling analogous to that 

 produced in the first stage of intoxication, 

 but unattended by pleasurable sensations." In 

 describing the effects of another experiment, he 

 says, " Having previously closed my nostrils and 

 exausted my lungs, I breathed four quarts of 

 nitrous oxide from and into a silk bag. The first 

 feelings were similar to those produced in the 

 last experiment, but in less than half a minute, 

 the respiration being continued, they diminished 

 gradually, and were succeeded by a highly 

 pleasurable thrilling, particularly in the chest and 

 the extremities. The objects around me became 

 dazzling, and my hearing more acute. Towards 

 the last respiration the thrilling increased, the 

 sense of muscular power became greater, and at 

 last an irresistible propensity to action was in- 

 dulged in. I recollect but indistinctly what 

 followed ; I knew that my motions were varied 

 and violent. These effects very rarely ceased 

 after respiration. In ten minutes I had recovered 

 my natural state of mind. The thrilling in the 



