480 NITROUS OXIDE. 



(c.) It was so volatile } that the warmth of the hand, although un- 

 der so great a pressure, converted it into vapor, and it boiled readily 

 by the difference between and 50. In refractive power it was in- 

 ferior to any known fluid, not excepting even the other condensed 

 gases. It remained fluid at 10. When the tube was opened in 

 the air, the fluid instantly burst into gas, and another tube being 

 opened under water, the fluid rushed again into the form of gas, 

 which was collected. 



(d.) To estimate the pressure, a trumpet shaped capillary tube, 

 containing a globule of mercury, after being graduated, by the pas- 

 sage of the mercury through the different parts of the tube, was seal- 

 ed at one end, and introduced into the larger tube, before it was 

 closed. The movement of the mercury indicated the pressure, and 

 when it became stationary, the force, at 45, appeared to be equal to 

 50 atmospheres, and 50 X 15 = 750 Ibs. upon the square inch. At 32 

 the pressure was 44 atmospheres, and 15 X 44 =660 pounds on the 

 square inch ; 12 degrees of temperature having added to its pressure 

 7 atmospheres, or 105 pounds, or nearly 9 pounds for each degree. 

 Mr. Faraday always subtracted 1 atmosphere for the air in the tubes 

 when the experiment began. 



9. EFFECTS ON ANIMAL LIFE. 



(a.) Warm blooded animals, confined in nitrous oxide speedily 

 die* and fishes expire in water impregnated with it.f For many 

 years after its discovery, no suspicion was entertained that it was res- 

 pirable. 



(b.) This gas is not only respirable, but it is the most powerful 

 stimulant known. ,f 



(c.) This was first ascertained by Sir H. Davy, in a series of 

 trials on respiration, some of them very hazardous, which he made 

 upon his own person ; the results may be found in his Researches, 

 from which the following passage is extracted, p. 487. 



" Having previously closed my nostrils, and exhausted 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 experi- 

 ment, (giddiness) ; but in less than half a minute, the respiration be- 

 ing continued, they diminished gradually, and were succeeded by a 

 sensation analogous to gentle pressure on all the muscles, attended 

 by a highly pleasurable thrilling, particularly in the chest and the ex- 



* Dr. Ure, (Diet. 2d Ed. p. 619,) says that mice die more speedily than when im- 

 mersed in nitrogen, hydrogen, or carbonic acid. 



t The blood acquires a purple color in consequence of the respiration of this gas, 

 and after death the muscles of animals are found to have lost their irritability. 



t It is said that if a little sulphate or muriate of ammonia be mixed with this ni- 

 trate, this salt will not afford an exhilirating gas. Ure. 



