ei8 Eleiftlc Forct cf Gunpov)der.—S!r!)iitian. 



That tlie conical form of the lower part of the bore where it unites with the chimbef 

 has a confiderable (hare iu producing this extraordinary effc-a, is, however, very certain, 

 as he has found by experiments made with a view merely to afcertain that fad. 



'Ilie remaining pages of the Count's paper are occupied by a computation, tending to 

 fliew, that the force of the elaftic fluid, generated in the combuflion of gunpowder, may 

 be fatisfactorily accounted for upon the fuppofition that its force depends fokly on the 

 elafticity of watery vapour or ftcam. For this purpofe he recurs to the experiments of 

 Mr. Betancour, publidicd in Paris, under the aufpices of the Royal Academy of Sciences* 

 in the year 1790, which fliew that the elafticity of fteam is doubled by every addition of 

 temperature equal to 30 o of FahrcnTieit. From the Count's reference, it appears that 

 the experiments were carried as far as 280 degrees of that fcale, in which cafe the prefiure 

 was found to be equal to about four itniofpheres. He aflirms, that there does not appear 

 to be any reafon why the fame law flioiild not hold iu higher temperatures, and has there- 

 fore extended his computations through thirteen more terms of the geometrical tries, the 

 laft of which affords an elaftic force equal to more than fixty-five thoufand atroofpheres. 

 As an cxcufe for not giving this computation in detail, I mult (imply remark, that fome- 

 thing more than a negative reafon fecms neceffary to juilify the extenfion of this law of in- 

 creafe from fo limited a fcale of experiments. For which reafon I fliall add no more of 

 this fpeculative part, than merely that the water of cryftallization in the nitre, and the 

 moifture which the charcoal may be conceived to retain, appear to be fully fulTicient to ac- 

 count for the explofive force by means of fteam only, if the dedudions from Mr. Betancour's 

 experiments be admitted. 



VIII. 



Obfervattom en Strontsan. By Citizen PelleTHR. Read to tht National Injlitutc 

 2cth April, 1796.* 



OTRONTIAN is at prefent confideredby many foreign chemifts as a peculiar earth. Its 

 difcovcry feems to me to be due to Dr. Hope, profeffor of chemiftry at Glafgow ; he bav- 

 in" firft defcribed its charaders and chemical properties in a diflertation which he publilhed 

 ^th November, 1793, and which has fince been printed in the Tranfadions of the Royal 

 Society of Edinburgh. This memoir isneverthelefs pofterior to Dr. Crawford's diflertation 

 on the internal ufe of muriate of barytcs, in which he announces that he thinks it probable 



that the ftrontian mineral contains an earth different from barytes f- _ 



M. Klaproth 



» Trinllattd from the Annates deCliimie, xxi. p. 113, by J. F— r. 



■I The fait obtained from the combination of ftrontian earth with nuriatic acid is much more fcluble in hot 

 witcr than m cold, and confequcntly cafily cryftallites by cooling ; muriate of barytcs, on the contrary, is 

 Bcarly as foluble in cold water as in hot, and cryftalliies by evaporation. 



An ounce of diflillcd water at the temperature of 70 degrees, diffolves 9 dr.ichms and 50 grains of muriate 

 •f ftrontian : the fame quantity of water, at the fame temperature, only diflblves 3 drachms and 3 5 grains of 

 muriate of barytes. 



The former prodvcci at leaft i; degrees of cold by it* foKition ; the latter rot more than 3 degrees at the 



■^ M«tutt> 



