SPECULUM. 



tranfcribe, in erder that the fame experiments may not be 

 fruitlcfsly repeated by future mechanicians. 



1. Copper and grain-tin, equal parts ; very bad, foft, and 

 of a blue colour. 



2. Copper with arfenic i ; but little different from the 

 firlt. 



3. Tin z, copper i ; much worfe than the preceding 

 ones. 



4. Copper 32, tin 16, arfenic 4, fixed with nitre ; black 

 and brittle. 



5. Copper 6, tin if, arfenic I ; very indifferent. 



6. Copper 32, tin 14, arfenic 2 ; a very good metal. 



7. Copper 32, tin 13I, arfenic I ; not quite fo good as 

 the fixth. 



8. Copper 32, tin 13!, arfenic i^ ; a good metal. 



9. Copper 32, tin 15, arfenic 2 ; mueh better than any of 

 the above. 



10. Copper 6, tin 2, arfenic i; compaft, but very yellowr 

 vphen polifhed. 



11. Copper 3, tin i^; compaft, and whiter than the 

 tenth. 



12. Copper 32, tini4i; a pretty good metal, but polilhes 

 too yellow. 



13. Copper 32, tin 15, arfenic 2, flint-glafs in powder 3 ; 

 very bright, but rotten. 



14. Brafs 6, tin i ; compaft, but too yellow. 



I J. Two parts of the eleventh compofition, and one part 

 of the fourteenth compofition ; compaft, but much too 

 yellow when polilhed. 



i6. Brafs 5, tin i ; fomewhat whiter than the fourteenth. 



17. Brafs 4, tin I ; a good metal, but rather yellow. 



1 8. Brafs 4, tin i, with arfenic Vt ; whiter than the fe- 

 venteenth. 



19. Brafs 3, tin i ; will not polifli well. 



20. Brafs 2, tin i ; of a fparry nature. 



ai. Tin 3, brafs i ; too foft, being only a kind of hard 

 pewter. 



22. Brafs and arfenic, equal parts ; a dirty white colour. 



23. Brafs, copper, and arfenic, equal parts ; a dingy 

 white. 



24. Brafs and platina, equal parts ; very difficult to fufe 

 and mix well toirether, is then malleable, and of a dingy 

 white colour, like the twenty-fecond compofition. 



2j. Copper 32, tin 14, crude antimony 4; black and 

 rotten. 



26. Copper 32, tin 14, crude antimony i ; blueifh, and 

 rough-grained. 



27. Copper 32, tin 15, arfenic 4, bifmuth 2 ; much too 

 rotten. 



28. Copper 32, tin 15, arfenic 3, bifmuth i ; much too 

 yellow when polifhed, and appears alfo porous. 



29. Copper 2, zinc I ; a pale malleable metal. 



30. Copper and zinc, equal parts ; flill malleable and 

 rough-grained. 



31. Copper 32, tin 15, arfenic 4, zinc 4; a good metal, 

 but does not take a high lultre. 



32. The thirty-fird compofition, fluxed with corrofive fubli- 

 mate ; a compaft and hard metal, but rather yellow when 

 polilhcd. 



33. Copper 32, tin 16; a moft beautiful brilliant compofi- 

 tion, but much too brittle and ?otten. 



34. Copper 32, tin 17; blueidi and rough-grained. 



35. Copper 32, tin 18; blucidi and rough-grained 



36. Brafs 2, zinc i ; nearly of a gold colour. 



37. Brafs and zinc, equal parts ; a pale gold colour, and 

 rough-grained. 



Vox.. XXXIII. 



38. Spelter 4, tin I ; very rotten. 



39. Copper and crude antimony, equal parts ; of a fparry 

 nature. 



40. Copper 32, tin i j, arfenic |;th of the whole ; a very 

 beautiful and brilliant metal, but tarnilhes when expofed 

 for fome time to the air. 



41. Silver and bifmuth, equal parts ; a yellowifh-white me- 

 tal, and not much harder than filver itfelf. 



42. Silver and tin, equal parts; a white metal, almoil like 

 filver itfelf, and much too foft for fpecula. 



43. Silver, tin, and bifmuth, equal parts ; a dingy white 

 colour, but much harder than the two preceding compo- 

 fitions. 



44. Copper 32, tin 15, filver i ; a beautiful compaft raetali 

 but polifhes rather too yellow. 



45. Copper 32, tin 15, filver 2 ; not fo white as the 

 preceding. 



46. Copper 32, tin 16, brafs 4, arfenic 2 ; rather too much 

 tin, as the compofition was of a blueiih complexion, and 

 rough-grained. 



47. Copper 32, tin 15, brafs i, filver i, arfenic l; a 

 molt excellent metal, being by much the whitell, hardeft, 

 and the moft rcfleftive I have ever yet met with. 



48. Common bell-metal ; polifhes very yellow. 



49. Common bell-metal 4, regulus of antimony i ; blueifil 

 and rough-grained. 



50. Common bell-metal 6, regulus of antimony i ; ftill 

 blueifh and rough-grained. 



51. Copper 32, tin 14, regulus of antimony i^, •u'lz. 1 oz. 

 to I lb.; too much antimony, it being of a blueifh colour, 

 and rough-grained. 



52. Copper 32, tin 13, regulus of antimony Vt ; blueifh 

 and rough. 



53. Copper 32, tin 13, regulus of antimony -J-^, viz. i oz. 

 to 2 lb.; a very fine metal, in appearance like thirty- 

 three. 



54. Copper 32, tin 13, regulus of antimony -^j viz. I or. 

 to 25 lb.; a beautiful metal, not much unlike forty-feven, 

 but not quite fo white. 



^^. Crude antimony 16, cawk-ltone i or 2 oz. ; a very 

 bright glaffy metal, like the common vitrum aiitimonii, 

 but by no means fit for mirrors. 



56. Copper 32, tin 16, vitrum antimonii made from the 

 cawk-ftone i oz.; a very indifferent compofition, as the 

 vitrum antimonii did not differ in its effefts from crude 

 antimony. 



57. Copper 32, tin 14, lead 2 ; no art can make this com- 

 pofition mix intimately, as the lead will always feparate 

 from the copper and tin. 



58. Copper 32, tin 16, regulus of antimony 3 ; black, and 

 much too rotten. 



59. Copper 32, tin 16, iron-filings 8 ; a blueifh-grey co- 

 lour, and rough-graiitcd, and appeared fomewhat like 

 tteel when broken through. 



60. Fifty-ninth compofition 8 0/.., tin i oz.; a little whiter 

 than the fifty-ninth, but flill too blue. 



61. Equal parts of fifty-nine and fixty ; ftill of too blue a 

 colour, and not clofe-graincd. 



62. Copper 32, tin 16, arfenic 3, iron-filings ^ of an oz.; a 

 pretty brilliant compofition, but much inferior to forty- 

 feven. 



63. Platina l 07,., brafs i oz., cawk-ftone red-hot J oz. ; 

 exceffivr'.y difficult to fufe, and of a dirty light brown co- 

 lour, and fomewhat malleable. 



64. Copper 32, tin 16, iron-filings 4, regulus of antimony 4, 

 and fluxed with corrofive fublimate ; an exceeding hard 

 and compaft metal, but of too blue a colour. 



3 Q <>5- Copper 



