Royal Society; 271 
loofe end outwards, and Hopped up the Trachea with a cork 5 
a few, but very violent ftruggles fucceeded, in whieh the 
Sternum was railed, as in the deepefl: infpiration, and thus the 
dog died : From the Hopping of his breath to the laft motion 
difcernible in any part of the body, was by a watch, two 
minutes j after this the Thorax was immediately thrown open, 
where the blood was leen ftagnating in the lungs 5 the Arteria^ 
^ulmonalis^ the right ventricle of the heart, with its append- 
ing auricle, and the two great trunks of ihe Cava were greatly 
diftended with blood ^ the Vena ^ulmonaliSy left auricle, and 
ventricle of the heart were in a manner empty : This expe- 
riment proves, that refpiration promotes the paffage of the 
blood thro' the lungs, and that this feems to be its principal 
ule. 
Black-Leadj by "Dr. Plot. Phil. Tranf. N° 240. p. 183. 
TH E mineral fubftance called Slack-Lead, found only at 
Kepwych in Cumberland^ and there called Wadt or 
Kellow^ by Dr. Merret, tsigrica fahrilis, from its ufe in fcor- 
ing, as the Rubrica fabrilis, or redoker, is To far from having 
any thing of metal therein, that it is incapable of fufion, much 
lefs of duflility • nor can it be reckoned amongft the fiones, 
for want of hardnefs -j it remains therefore that it be clafTed 
amongft the earths, tho* it diflfolve not in water, as moil earths 
will, except ftiff clays and okersj amongfi: the latter of wiiich 
Dr. ^Plot conjefiures it may be reckoned, it feeming to be a 
fpecies of clofe earth, of very fine and loofe parts, fo burnt, 
that it is become black and Ihining, difcolouring the hands, as 
all okers do 5 whence the moll proper name that can be given 
it, perhaps, is Ocbrea nigra, or Slack Oker, being a ftony 
Ibrt, as there are ftony forts of the red and yellow ckers, as 
well as clay. 
^he Kubricks for the Seat of Eafler, according to the Ju- 
lian Account, explained y by 'Dr. Wallis. Phil. Tranf. 
N'^ 240. p. 185. 
TH E fundamental rule of the Nicene council, which we 
pretend to follow for the keeping of Eafter, is to this 
purpofej EafterdTiyis to be that Sunday, which falls upon, 
or next after, the firfl full moon, which happens next after 
the vernal Equinox 5 this vernal Equinox was then obferved to 
fall on the 21ft of March, tho' it now falls on the nth of 
Marchi or fometimes on the loth of March':, and therefore, 
inftead 
