( !00l ) 
gathers upon falling into the Porringer, and which 
ftick to it s Surface, the CrA^Amentum is kept from fink- 
ing, and Teems to float upon the top of the Serum, 
Thefe Accidents Teem to have given tiie firft occa- 
fion to that Opinion, which, I think, has been gene- 
rally entertain'd by thole who have writ upon this 
Subjed:, namely, that the globular part of the Blood 
is fpecifically lighter than the Seram, in which it 
fwims. 
But that which has fo fully eflablillit this perfua- 
fion, is the Authotity of the late excellent Mr. Boyle, 
who, among the many valuable and curious Experi- 
ments he has given us in his Natural Hiftory of Human 
Blood, has left the following ones upon this Subjed. 
The fpecifick Gravity of Serum of Human Blood 
was found by weighing a piece of Sealing Wax firll in 
Serum, and afterwards in Water, to be to the fpecifick 
Gravity of Water, as 10x4 to 1000. 
In a fecoiid Experiment, which for grpter accuracy 
was made with an Inflrument contriv’d* on purpofe, 
the fpecifick Gravity of Serum was found to be to that of 
Water, as 1194, to 1000. 
In a third Experiment made by the fame Inflru- 
ment, and with Serum from the Blood of another Per- 
fbn, it’s fpecifick Gravity appear’d to be 1186. 
The Medium between thefe two lalt Experiments is 
1190, which has fince been univerfally receiv’d for the 
fpecifick Gravity of Serum of Human Blood, the firfl 
Experiment being declar’d by Mr. Boyle himfelf to be 
lefs exadly made than the other. 
The fpecifick Gravity of Human Blood was found 
by Mr. [Boyle, to be to that of Water, as 1040 to 1000 ; 
though on account of difficulties by him mention’d, 
he was far from being fatisfy’d with this Experiment, 
and recommended the thing to farther tryal 5 . 
Thefe 
