484 On' the mutual Affinities of the Earths. 



common folvent of the two earths. I think it the more proper to Infift on this obferva- 

 tion, becaufe magnefia and alumine themfelves afford a ftriking example. If they be 

 precipitated together from their folution in the muriatic acid by pot- afli, they contract an 

 union fufficiently intimate to prefent the chara£ler of a peculiar earth, infomuch that pot- 

 afli no longer adls upon the alumine. This fadl, which is of great value with regard to the 

 prefent queftion, was obferved by citizens Clouet and Hachette in a feries of experiments, 

 in which they engaged for the purpofe of aflifting me to fill up certain blanks in a table, in 

 which I propofed to give all the direft combinations of fimple or undecompofed fub- 

 flances. 



§ 2. Experiments in the dry Way. 



"With regard to the affinities of earths to each other in the igneous fluid, or in the dry 

 way, fome of the fa£ts which fupport it have been known long before the .true caufe was 

 fufpe£led. The refults which relate to the property called fufibility were alone perceived, 

 and no farther refearches were made to explain what daily happens in the workshops of 

 manufa£turers, I mean the vitrification of lime and filex by each other. 



Three years ago I announced Nos. 35 and 39 of my experiments on the fufibility of the 

 earths by their mutual attra£tion, that equal parts of barytes and filex afforded in the cru- 

 cible a very diftin£t vitriform produft, and that equal parts of barytes and lime afforded a 

 tianfparent glafs*. After having mentioned thefe two refults, I fhall confine myfelf to 

 add in this place thofe of fome new experiments, diredted particularly to the ftrontian and 

 jargon earths. 



Experiment r8. Strontian and filex mixed in equal portions, and placed in a faucer 

 of platina in a fire of 140 pyromctric degrees, afforded a fine white frit, nearly equal in 

 appearance to enamel, which flightly fcratched glafs. A few fmall tranfparent vitreous 

 globules were feen, and fome adhered to the vefl'el of platina. 



Experinient 19. The mixture of ftrontian and lime alfo placed upon platina, after 

 having undergone a heat of 153 degrees, left a hard white frit, porous beneath with bub- 

 bles, without adherence to the vefielj likewife prcfenting fmall vitreous globules, and fome 

 knobs of enamel. 



Experiment 2o. The jargon earth treated in the fame manner with filex, produced by heat 

 of 140 degrees a yellowifh grey frit, pulverulent at its furface, with fome white vitreous 

 points of a beautiful tranfparence ftrongly adhering to the platina, and fo hard as to cut 

 glafs. 



Experiment 21. The mixture of jargon earth and lime afforded in the fame circum- 

 Itances a grey frit of little folidity, or even granular, and one fmall globule of enamel 

 adhering to a point of the crucible of platina. 



Thefe fafts are doubtlefs fufficient to prove, that thefe earths have alfo a fufficient affi- 

 nity to each other to produce vitrification, when the due proportion fhall have been dc- 



• Journal Polytechnique 3 cabief, pag. J06 .& 308. 



tcrmined 



