Compojttioni of Speculums,~-On Shell and Bone, 529 



24. Brafs aTld platina, equal parts ; very difficult to fufe and mix well together, is then 

 malleable, and of a dingy white colour like 22, compofition. 



25. Copper 32, tin 14, crude antimony 4 ; black and rotten. 



26. Copper 32, tin 14, crude antimony i ; blucifli and rough grained. 



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



28. Copper 32, tin 15, arfenic 3, bifmuth 1 ; much too yellow when polifhed, and ap- 

 pears alfo porous. 



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



30. Copper and zinc equal parts ; Itill malleable and rough grained. 



3,1. Copper 32, tin 15, arfenic 4, zinc 4; a good metal, but does not take a high 

 luftre. 



32. The 31ft compofition fluxed with corrofive fubllmate ; a compaft and hard metal, 

 but rather yellow when polifhed. 



33. Copper* 32, tin 16; a moft beautiful,, brilliant compofition, but much too brittle 

 and rotten. 



34. Copper 32, tin 17 ; blueifh and rough grained.. 



35. Copper 32, tin 18 ; blueifli and rough grained.. 

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



37. Brafs and zinc equal parts ; a pale gold color, and rough grained. 



38. Spelter 4, tin i ; very rotten. 



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



IT. 



Experiments and Ohfervations on Shell and Bone. By Charles Hatchett, EJq. F. R. 5. 



f Concluded from page 506. J 



X HE bones of fifh, fuch as thofe of the falmon, mackarel, briUi and fKate, afforded 

 phofphate of lime ; and the only difference was, that the bones of thefe fifh appeared in 

 general to contain more of the cartilaginous fubftance relative to the phofphate of lime, 

 than is commonly found in the bones of quadrupeds, &c. 



The different bones alfo of the fame fifh were various in this refpeft ; and'thc bones 

 about the head of the fkate only differed from cartilage by containing a moderate propor- 

 tion of phofphate of lime. 



It is at prefent believed, that phofphate, with fome fulphate of lime, conflitutes the 

 whole of the ofTifying fubflance; and perhaps- the formation of bone from cartilage de- 

 pends only on the phofphate of lime; but whether this is the cafe or not, it is fit that I 



* Unlefs the copper is very pure, this compofition will be of a dark blue colour, as 15 ounces of grain , 

 tin 'v«ill generally faturate two pounds weight ef copper, 



fhouldi 



