TOL. XC.] PHILOSOPHICAL TRANSACTIONS. 641 



stirred or agitated. — Exper. Q. The recent serum, drawn from patients afflicted 

 with inflammatory complaints, was illuminated pretty much in the same manner 

 as in the 8th experiment; and often retained light above 48 hours. 



Urine. — Exper. 10. Mackerel-light being mixed, by strong agitation, with some 

 fresh urine from a healthy person, a glimpse of light was retained at first, and 

 then was gradually extinguished. But stale and pungent urine, being incorporated 

 with luminous matter, had a still greater extinguishing effect. 



Bile. — Exper. 1 1 . Some bile, taken from a person who died of a suppression of 

 urine, had herring-light mixed with it, which soon became extinct. Another 

 trial was made with a different bile, and with the same result. 



Milk. — Exper. 12. Human milk not being easily obtained, some mackerel-light 

 was incorporated, by agitation, with 2 oz. of fresh cow's milk, which was thus 

 rendered finely luminous, and continued shining above 24 hours. Fresh cream 

 also retained some light; though it was not so visible as with milk, owing probably 

 to its thickness. But, when either milk or cream turn sour, they contract a very 

 extinguishing property. A quart of milk was kept 5 days, in a moderately cool 

 place, in June ; by that time it was changed into a mixture somewhat resembling 

 curds and whey, that is, into a soft smooth coagulated part, and a very thin one, 

 both which were acidulous. Some fine mackerel-light was mixed with 2 oz. of 

 each of them, in separate phials, and they extinguished it immediately. 



X. Experiments for Decomposing the Muriatic Acid. By Mr. Wm. Henry, p. 188. 



One of the first objects, in the analysis of a compound body, should be its 

 complete separation from all other substances, which, by their presence, may tend 

 to introduce uncertainty into the results of the processes that are employed. But 

 it is seldom that a simplicity so desirable can be attained in the objects of chemical 

 research; for, agreeably to a known law of affinity, the last portions of any sub- 

 stance are separated with peculiar difficulty; the force of attraction appearing to 

 increase, as we recede from the point of saturation. In a liquid state, the muriatic 

 acid is a totally unfit subject for analytic experiment; for, in the strongest form 

 under which it can be procured, it still contains a large proportion of water. 

 This watery portion, besides the complexity which it introduces into the results of 

 experiments, prevents any combustible substance that may be applied, from acting 

 on the truly acid part; because that class of bodies, having less difficulty in at- 

 tracting oxygen from the water than from the acid, will necessarily take it from 

 the former source. The state of gas therefore is the only one in which the mu- 

 riatic acid can become a proper object of analysis. 



In the series of experiments on this gas, which I am now about to describe, I 

 employed the electric fluid, as an agent much preferable to artificial heat. This 

 mode of operating enables us to confine accurately the gases submitted to experi- 

 ment; the phenomena that occur during the process may be distinctly observed 

 and the comparison of the products with the original gases may be instituted with 



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