HQO Rtporl oti the Art of making fun Cutlery, 



pofed to a gradual heat while floating at the furfaee of the fufible mixture. The appear- 

 ances are as follow : 



No. I. taken out at 430° of Fahrenheit. This temperiiture leaves the ftecl in the moft 

 excellent (late for razors and fcalpals. The taTnitli, or faint yellowiih tinge it produces, is 

 too evanefcent to be obferved without comparifon with another piece of poliflied fteel. 

 Inftruments in this (late retain their edge much longer tlian thofc upon wlxich the aflual 

 ftraw colour has been brought, as is the common praiSlice. Mr. S. informs me, that 430° 

 is the loweft temperature for letting down, and that the lower degrees will not afford it 

 firm edge. 



No. 2 at 440", and 3 at 450°. Thefe needles differ fo little in their appearance from 

 No. I, that it is not eafy to arrange them with certainty when mifplaced. 



No. 4 has the evident tinge which workmen call pale ftraw colour. It was taken out at 

 460°, and has the ufual temper of penknives, razors, and other fine edge tools. It is much 

 fofter than No. 1, as Mr. Stodart affures me, and this difference exhibits a valuable proof 

 of the advantages of this method of tempering. 



Nos. 5, 6, 7 and 8, exhibit fucceJTive deeper fliades of colour, having been refpe£tively 

 taken out at the temperatures 470°, 480", 490", and 500''. The laft is of a bright brownifli 

 metallic yellow, very flighfly inclining to purple. 



No. 9 obtained an uniform deep blue at the temperature of 580". The intermediate 

 fliades produced on fteel by heats between 500' and 580° are yellow, brown, red, and 

 purple, which are exhibited irregularly on different parts of the furfaee. As I had before 

 feen this irregularity, particularly on the furfaee of a razor of Wootz*, and had found in 

 my own experience, that the colours on different kinds of fteel do not correfpond with like 

 degrees of temper, and probably of temperature in their production, I was defirous that 

 fome experiments might be made upon it by the fame (kilful artift. Four beautifully po- 

 liflied blades were therefore expofed to heat on the fuGble metal. The firft was taken up 

 'wben it had acquired the fine yellow, or uniform deep ftraw colour. The fecond re- 

 mained on the mixture till the part neareft the ftem had become purpleifh, at which period 

 a number of fmall round fpots of a purpleifli colour appeared in the clear yellow of the blade. 

 The third was left till the thicker parts of the blade were of a deep ruddy purple, but the 

 _com:ave face ftill continued yellow. This alfo acquired fpots like the other, and a flight 

 cloudinefs. Thefe three blades were of caft fteel ; the fourth, which was made out of a 

 piece called Styrian fteel, was left upon the mixture till the red tinge had pervaded alrnoft 

 the whole of its concave face. Two or three fpots appeared upon this blade, but the greater 

 part of its furfaee was variegated with blue clouds, difpofed in fuch a manner as to produce 

 thofe waving lines which in Damafcus fteel are called the water. Two refults are more 

 immediately fuggefted by thefe fafts; firft, that the irregular produ£lion of deep colour 

 »pon the furfaee of brightened fteel, may ferve to indicate the want of uniformity in its com- 



* On Wootz, fee Pearfon in the Phil, Tranf. 



pofition» 

 8 



