C $99 ) 
lour, and oilier Venues. You have alfo this difference 
in the manner of exhibiting, in Mr. Boyle's Experiment 
you have the Fiieings of Copper contiguous with your 
Menflruum, in ours you have a clear Golourle.6 Liquor, 
and no Materials at all in your Glafs to give the leaft 
Umbrage to this fudden change orXolour 5 but this can- 
not be performed without forne Encheirefii and an Appa- 
ratus extraordinary. 
'In making the Experiment you will obferve, for 
4 four, five, or fix days the Tiniture will be growing 
•deeper and deeper, and then will keep a fiand for two 
' or three days more or left, and afterwards will gradual- 
* ly decline until it become quite pale, and void of all 
* Colour. When it is in this flate, the eafieft way of 
4 performing the Experiment for your own fatisfadrion, 
* is to decant this clear Spirit into a Glafs fo as to leave 
€ all the Fiieings behind, and that will demonftrate that 
* the Fiieings did not give thisTin&ure de novo^ but that 
* it belongs to the influence of the Air. Bue in cafe you 
4 are furnilh'd with an Air-pump, and can pour off this 
c palid Liquor in zVacuo Aeris, and there flop it up fe- 
4 curely, you may then preferve it fo long as you pleafe, 
*and exhibit it to advantage, which is the way I com- 
< monly ufe. You may alfo obferve, that fo foon as 
* you let in the Air, the upper Superficies immediately 1 
1 tinges firft, and fodefcends deeper and deeper until it 
4 has penetrated the whole, and this it does the fooner, if 
' the Glafs be wide, and the Liquor by confequence have 
$ a large Superficies: Or if you pour it out of one Glafs 
* into another, the Air makes a more fudden change of f 
1 the whole. 
That Liquors ffiould lofe their Tindtures is not to be 
wonder'd at, for even Ink it ftlf by (landing ftill will 
lofe much of its Tin£hire, and fo do the Tin&ures of ma- 
x ny Minerals, Tin&ure of Sulphur, and of Salt of Tartar 
will lofe their Tin&ures, and many Vegetables are not 
long; 
