[ 4 ] 
form, upon the fuppofition that pure gold was, ac- 
cording to Ghetaldus , juft 19 times as heavy as 
water. And this I have rather chofen to do, than 
to make ufe of his Lordfhip's own weight of water 
given in the table, which in the manner he took 
it could not be very exaft, and which befides would 
not have brought out the fpecific gravity of pure 
gold more than 18 times as much ; and that of the 
other metals in proportion. This table contains in 
all 78 articles. 
There are alfo in the third volume of the fame 
edition of his works, p. 223, Certain experiments 
wade by the Lord Bacon about weight in air and 
water. Thefe are truly hydroftatical , but very im- 
perfect, I have not therefore inferted any of them 
in the following collection. 
Marinus Ghetaldus , a nobleman of Ragttfa , pub- 
lifhed in quarto at Rome , in 1603, his treatife en- 
titled, Tromotus Archimedes , feu de variis corpo - 
rum generibus gravitate et magnit udine comp ar at is, 
wherein he has given a companfon between the fpe- 
cific gravities of water and eleven other different 
fubftances, from his own hydroftatical experiments 
made with care and cxaCtnefs. Thefe I have in- 
ferted : exp re fling the numbers as they ftand in his 
own book, but I have afterwards alfo for uniformity 
reduced them to the decimal form. I have befides 
at the end tranferibed at large the two tables of 
this author, in which every one of the twelve forts 
of bodies he treats about is fucceffively compared 
with all the others, both in weight and magni- 
tude. 
Father 
