^4^ Eudlomettrs. — Ftifi(.n of Earths. ^^Prujfc Colouring Malttr. 



gave the refult with the requifitc fpeed ami accuracy. Guyton difcovcrcd, that by heating 

 the fujphur* the comViination is made inftaiitjy. He therefore advifes to take a fmall retort 

 filled with water, to plicc therein the fmall piece of fulphurc, then to introduce the air and 

 heat with a taper to that place on which the fulphure reds. The abforption of the oxygens 

 io iiiimcciatciy made, and the defired refult afcertained. 



By this invention, which contributes to the accuracy and value of an inftrument greatly 

 ufcful in meteorological obfcrvations, Guyton has rendered a real fervice to philofophers. 



Gottling had maintained, in a memoir publithed in Gren's Journal, that phofphorus 

 burns in azotic gas, forms an acid by this combuftion, and does not burn in oxygenous gas. 

 Berthollet made fcveral experiments on the combination of phofphorus with different gafes. 

 He found, i. That the phcifphorus does not combine with oxygenc at the ordinary tempe- 

 rature, but requires a more elevated temperature to produce combudion. 2. That phofplio. 

 rus is foluble in the azotic gas ; and that, by means of this folution, it burns with oxygenous 

 gas at the ordinary temperature, and appears luminous in the dark. 



By means of thefe experiments, Berthollet explained tlie extraordinary phenomena which 

 Gottling, Lcmps, and Lampadius, had obferved ; and he imagined that phofphorus might 

 be ufed to .Ticafure the quantity of oxygene gas contained in the air of the atmofphere, or any 

 other gas containing azote. 



This new eudiometer has an advantage over other inftrumciits of the fame nature, by 

 (hewing the precife inftant of the total abforption of oxygeye, which happens when no 

 More white vapour is feen in the day light, nor light in an obfcure place ; but it has likewifc 

 the inconvenience of requiring the prefence of a quantity of azote fufhcicnt to dilTolve the 

 phofphorus rcidily before its combination with oxygene. 



In the analyfis of the calcedony of Creufot, of which the corrftituent parts proved to be, 

 filex 86.c8, iron 768, alumine 4.1 r, lime 1.16, lofs i.o, Guyton aimed lefs to afcertain 

 the proportions of ingredients in a ftoiic fo variable, than to prcfcnt to the pupiK of the fchool 

 an exanple of the anilyfij of (lones. In this refpeil his memoir is one of the moft inftruc- 

 thre in the colletlion. 



A great number of chemifls, with Pott at their head, have K^bourcd at the folution of the 

 intererting problem of the fufibility of earths, upon which they have made many fcientific ex- 

 periments. To thefe Guyton has added a great number of his own. He firfl tried the fufi- 

 bHitics of the earths with oxygene gas, and afterwards the efFed of carbonate of foda, 

 calcined borax, pulverized ammoniacal phofphate of foda, and the red oxide of lead. He 

 afterwards mixed the earths two and two with the piecetlitig fluxes, and at laft terminated 

 by the a€Hen of the earths upon each other, and that of calcareous phofphate on each of 

 them. The feries of facts mud be confulted in the memoir itfelf, as their conneiSlion does 

 not allow of detached ext'iidls. 



Clouet had publidicd in a memoir, that the prndic colouring principle might be obtained 

 by pafTmg ammoniacal gas through ignited charcoal. The expcrimi nts related by Bonjour, in 

 the third Cahier of the Journal of the Polytechnic School, confift merely of the procefles 

 he made ufe of, and the trials lie made in the preftnce of Clouet to verify the phenomenoi^ 

 he iiad annoanccd, and which, after a hioft careful examination, proved to be in every 

 rcfpeft agprteableto the account which was publilhed. 



X The 



