The works of the Honourable Robert Boyle, Esq., epitomiz'd by Richard Boulton ... ; illustrated with copper plates.

TITLE VI. Of the Consistence and Specifick Gravity of Human Blood.

A Compact Body, which in the Air weigh∣ed fifty eight Grains, and in Water weighed six Grains and ¾, in rectifi'd Spirit of Human Blood weighed but five Grains and ¼; and what was considerable, was, That a piece of Amber would not subside to the Bottom, but kept floating upon the Top, and if plung∣ed into it, would emerge again.

As for the Degree of the Fluidity of the Blood, or its immunity from Tenaciousness, tho' divers other Alkalizated Liquors, as Oyl of Tartar per deliquium, fixed Nitre resolved per deliquium, a Solution of Pot-Ashes, are sensibly unctuous, and but languidly fluid, yet I ob∣served that Spirit of Human Blood did not appear more Unctuous than common Water.

And whereas it is commonly found, That as Liquors are more spirituous, so the Bubles raised by Agitation, soonest disappear; I have observed that the Spirit of Blood was almost as soon clear of them as Spirit of Wine; and when some Drops of it were let fall, they manifestly appeared less than Drops of Wa∣ter.

To discover the subtlety of the Parts of Human Blood, we so prepared common Wa∣ter, by Infusions made in it without Heat, that by putting one single Drop of our Re∣ctified Spirit of Human Blood into ten Oun∣ces and four Scruples of the prepared Water, and lightly shaking the Viol, there appeared throughout the Liquor a manifest Colour, whereof no Degree was discernible before; so that it dispersed it self through a thousand times as much Water, and produced a mani∣fest Change in the Colour of it: And tho' this Computation is made upon the common suppo∣sition that a Drop of Water weighs a Grain, yet tho' it weighs more a little, the Difference is recompensed, since having dropped ten Drops of common Water into a common Bal∣lance well adjusted, and having likewise drop∣ped ten Drops of this Spirit, we found that the last were not only less in bulk, but lighter, since they weighed not above four Grains, so that the Proportion to which it extended it self, may be said to be as one, to betwixt 4000 and 5000; and this subtlety of the Parts of the Spi∣rit of Human Blood will appear to be yet much greater, if we consider, that some Part even of this Drop must needs be Phlegm.