730 P'HILOSOPHICAL TRANSACTIONS. [aNNO I79O. 



all of a stimulating nature cannot be ventured on with safety. And hence if the 

 observations made on the efficacy of this acid as an external application, should 

 be confirmed by future experience, it must be left to the judgment of the surgeon 

 to determine both the degree of its dilution, and the cases in which it may be 

 employed with advantage. 



The dephlogisticated marine acid, as is generally known, has the power of 

 destroying the colour, the smell, and perhaps the taste, of the greater part of 

 anitnal and vegetable substances. We have seen that it corrects the fetor of 

 putrid flesh. And he has found that, when it is poured in suflicient quantity on 

 hemlock and opium, these narcotics speedily lose their sensible qualities. As it 

 appears therefore to possess the power of correcting the vegetable, and probably 

 many of the animal poisons, it seemed not unlikely that it might be useful as an 

 internal medicine. Conceiving that its exhibition would be perfectly safe. Dr. C. 

 once took 20 drops of it diluted with water. He soon afterwards however felt 

 an obtuse pain, with a sense of constriction, in the stomach and bowels. This 

 uneasiness, notwithstanding the use of emetics and laxatives, lasted for several 

 days, but was at length removed by drinking water impregnated with sulphureous 

 hepatic air. He afterwards found that the manganese, which had been used in 

 the distillation of the acid, contained a small portion of lead. 



Dr. Ingenhousz informed Dr. C. that a Dutchman of his acquaintance, some 

 time ago, drank a considerable quantity of the dephlogisticated marine acid: the 

 effects which it produced were so extremely violent, that he narrowly escaped with 

 his life. If therefore this acid should hereafter be employed as an internal medi- 

 cine, it would be necessary to prepare it by means of manganese that has been 

 previously separated, by a chemical process, from the lead and the other metals 

 with which that substance is usually contaminated. 



XXllI. On the Satellites of the Planet Saturn^ and the Rotation of its Ring on 

 an Axis. By Wm. Herschel, LL.D., F. R. S» p. 427. 



In Dr. H.'s last paper on the planet Saturn, the principal object of which was 

 to give an immediate account of the most interesting phenomena that had oc- 

 curred till the beginning of November, many things were left unnoticed for want 

 of time to treat of them with sufficient accuracy; but having now before hira the 

 whole series of observations from July 18 till Dec. 25, 1789, he enters into a 

 proper examination, assisted by such necessary calculations as then could not 

 conveniently be made. 



One of the principal motives which have induced Dr. H. to hasten this inquiry, 

 is the frequent appearance of protuberant and lucid points on the arms of the 

 ring of Saturn. He has mentioned before that such phenomena had been 

 resolved by the situation of satellites that put on these appearances; but as his 



