417
march 10th. 1679/80
Present S
r. Ioseph Williamson. M[r. Aston. M
r. Haughton. M
r. Hooke M
r. Haak
M
r. Perkins
The weight of Refined Siluer was examined fir
st in air and then in
water and was found {in air 136 / in water 122 1/2.} whence
the grauity to water
as 10 2/27 to one. then an equall weight of copper was examined.
and found {in air. 136 / in water. 118 1/2} whence its specifique grauity to water
as 7 27/35 to 1. then they were put together in a crucible or melted
and being weighed againe when mixt the ma
sse weighed {in air 268 2/16 / in water 238 3/16}
whence
the weight to water as 8 458/479 to 1. But suppo
sing a perfect
mixture w
thout penetration it should haue been. 9 and somew
t more
then a third. we hammerd it and found it very hard & tough &
cutting of it w
th. a chizzell we perceiued that the mixture was not
soe perfectly made but that some parts were more brown then
the other. therefore we melted it againe and found its weight
in air 264 / in water {in air 264 2/8 / in water 236 3/8} whence its Specifique Grauity to water was as
9 107/223 which is somew
t heauier than it ought to haue been without
penetration
We tryd al
so a crown peice
. . . . . . . . and found its weight
{in air 471 1/4 / in water 425 1/4.} whence it weight to water was as
10 45/184. soe that it seemd to haue some Lead or tin mixed w
th it
rather then copper. it being heauier then Refined Siluer where
as copper makes it lighter.
Ref: CELL/RS/HF_419 © Centre for Editing Lives and Letters
