:«2 Colours obtained by Copper, 
in any Menftruum, they are ftrongly at¬ 
tracted by Iron ; infomuch that if a Needle 
or the Point of a Knife be held, but for a few 
Minutes in a Solution of blue Vitriol, or if 
blue Vitriol be wetted and rubbed upon 
Iron, it will prefently be cafed over with 
Copper : and yet when thefe fame Particles 
are collected into a Mafs of Copper, there 
feems no Attraction between that Mafs and 
a Mafs of Iron, nor has the Magnet any 
fenfible EffeCt on Copper. 
Copper affords a blue or a green Tinc¬ 
ture, according to the Menftruum wherein 
it is dilfolved ; and therefore is fuppofed to 
fupply Colour to the Emerald, Sapphire, 
T urquoife, Lapis Lazuli, Lapis Armenus , 
and moll other Stones and Minerals that 
are either green or blue, as well as to 
the Subjed we are at prefent treating of. 
■ The amazing Variety of Blues and Greens 
deducible from this Metal, and the Chan¬ 
ges of one into the other, are exceeding¬ 
ly worth the while ot every curious Per- 
fon to fatisfy himfelf about by a Train of 
- eafy Experiments; the Way of making 
which may be found in Boyle s Treatife 
of Colours, in Boerhaave s Chemiftry, as 
tranflated by Dr. Shaw, Vol. II. page 342* 
&c. and in Bill's Letter, printed at the End of 
his Lheophrajlus, on the Effecis of different 
■ Menfruumson Copper ; where we are informed, 
that, of the Mineral Acids, Spirit of Sea-Salt, 
