( 447 ) 
one of them in vacuo^ the other in the free Air, there 'was let fall in- 
to both ac the fame cime two equal parcels of Lime^ one into each ; 
and it appeared, that that which was in vacuo did indeed throw up 
fomebig bubbles , but yet fewer of them than that which was in 
the Air : And having taken if,an hour after, out of the Recipient, 
and ftirr'd the Lime^ it was found to have only the confidence of 
Dirt, vi'hereas the other had the confiftence of flecked Lime. The 
reafonof which may perhaps be, that the VolatilSaks of the Lime 
do exhale vvhilft the Recipient is emptying. 
There w^as alfo feme Plaifter of Paris flecked in vacuo ^ and the 
Ebullition of it did there appear much more than it doth in the 
open Air. When it is not touched, the bubbles that iffue out leave 
great holes in it, and then it fettles very un even , but taking care 
to ftir it until the bubbles be come forth , and prefling it when it 
begins to fettle^it becomes very fmooih,and haih not fo many little 
holes as the common Plaifter. 
particular ac county given by an anonymom French Author in his 
hook of Origin of Fountalns,/>ra/^^ 1674 Paris ^ tojheWj 
that the Rain and Snovp^ waters are fufficient to make Fountains 
and Rivers run perpetually , 
IN order to give a grofs Eftimat of the quantity of 
Rain'^, compared with the quantity of Water running away 
in Sprinp^s and Rivers ; it will be neceffary HtVl 
* r r ' i r r *The like to whicfa 
to agree of the way of meafuring thefe two fores jj^th been attempted 
of Water. Thofe that make profeflion of govern- iieres and propofed 
ing and conveying Spring- waters, fay, thacacu- f^Jeyeats finTJ 
bick inch of water yields in twenty four hours Srxftr,rrr«;7,whoby 
14.4 muids, (the name of a Fr^';?^^ meafure, hold- ^^e contrivance of 
. ^ ^ , . ^ , n ' • I J 1 a Rain-bucket had 
mg 280 trench pints ;) others lay, it yields but taken an accounrof 
70 of tbanmeafure. Formyparr^ I havereafon ^^ii the Water that 
to believe, that it yields 83 of thismeafure, ar.d ^t'^rmeVand b^hh 
follow thofe that fay, that a VeiTel of two foot ,Weather-clock had, 
deep, long and broad, holds one of Water, ^'^^^^^S noro"^^^^^^^^^^ 
ken in the meafu- 
ring of the quantity of Rain thatfalls, butalfo the time when it falls, and how 
much at each time. Which Inftrument, if put into practice, would be of excel- 
lent Ufe, forafmuch as it may alfo ferve > by feme add itioHS made thereunto by Af« 
^0(?ib, to record the weight of che Air,thedrought,moifture , heatand cold of the 
Weather, the Sun fhine , the quarters and Hrength of the Winds : And all this 
to be performed by one only motion, driving all the parts of the Inftrument j which 
is therefore the more confiderable, that it felf records its own efTe&s. 
This 
