291
Feb. 27. 1678/9.
m
r. Henshaw the vice presid
t. tooke the chair
The minutes of febr: 20 being Read gaue occa
sion to Di
scour
se
further about the Hypotheses by w
ch. the Phenomena of the
Barometer might be explaind And particularly whether
vapours a
scending or Raine De
scending through the air
Did charge the pre
ssure of the air beneath them w
th their
whole weight.
vpon the mention of salt peter. S
r. Iohn Hoskins Rela
ted the way of making it in the ea
st Indies, to be thus -
The Inhabitants of
the Bay of Bengala Dig small
trenches in the earth which being filled /with/
by a sort of nitrous water is ^ /impregnated w
th nitrous partcles which being/ sufferd to Euaporate in the sun till all the moys
=ture be exhaled when there will be found about the
bottom & sides of the trench much salt peter, which they
Rake together and soe keep them.
Also that much was scraped off from old walls
m
r. Henshaw affirming that in
. . . raking this nitrous
salt
together they . . . after this manner they Rake together
w
th the /pure salt great/
pur quantitys of the Dro
sse & earth w
ch they vsuall fill it w
th it
Also that there was some of this Rifined in India But that
for the mo
st part they bring it vnrefined and tis here Re
fined by the help of Ashes or some Alcalizate salts.
/now the greate
st part is refined in India -/
m
r Henshaw was of opinion that salt peter of it self contei
ned noe alcalj. but that it was produced by the fire
m
r. Hooke mentiond the way of making salt peter w
th.
Sp
t. of niter and Alcalj Salt mixed whereby It appeared that
salt peter might be compounded of An alcalizate &
an acid salt mixed together and soe coallescing into salt peter
Ref: CELL/RS/HF_293 © Centre for Editing Lives and Letters
