[ 74 ] 
with all the colours from all the metals. They are 
not indeed difpofed in fo regular and beautiful a man- 
ner as in the rings I produced ; but they equally de- 
monftrate, that none of the metals difcovers the leaf!; 
preference to any one colour more than another. A 
variety of other very extraordinary appearances oc- 
curred in the courfe of Mr. Canton’s experiments in. 
melting wires. 
In what manner thefe colours are formed, it may 
not be cafy to conjediure. In Mr. Canton’s method 
of producing them, the metal feems to be difperfed 
in all directions from the place of explofion, in the form 
of fpheres, of a very great variety of fizes, tinged with 
all the variety of colours, fome of them too imall to 
be diftindtly vifible by any magnifier. In my me- 
thod, it fhould rather feem that they are produced in 
a manner fimilar to the production of colours on fteel 
&c. by heat /. e. the furface is afFedted, without the 
parts of it being removed from their places, certain 
plates only, or laminae , being formed, of a thicknefs 
proper to exhibit the refpedtive colours at certain dil- 
tances ; and that the thicknefs of thefe plates is con- 
tinually changing by the repetition of the explofions. 
N. B. The battery made ufe of in the abovemen- 
tioned experiments was of twenty one fqu are feet 
of coated glafs. 
Received: 
