C 4095 ) 
round and a little flatted '5 of m oKve colour , mark^' 
ed with red fpecks 5 like coagulated blood ^ and fo po« 
liftied and fliining,thac ic reflefted Images* It was wrapped 
up in a membrane full of fatjand faftnedon both ends to the 
back boncj over againft the Kidneys* Though this Horfe 
had been dead twelve hours before it was opened > yet was it 
ftill very warm, apd kept that warmth above fix hours after 
iG was opcEied. . This ftoije is kept among the Rarities of Sig- 
nor B^r^^/^w^j an It|ilianRiding-maftcr. 
An Accmpt of [ome Books. 
I, An ESS At about the Grigme and Vertues of GEMS ; by th 
HofWurableKohcnBoyl Efquire, Fellow of the R. Society; 
Panted at London^ 1672^ m $^. 
TH E defign of the Noble Author of this excellent Trea- 
tife being,to propofe updJiiftorically to illuftrate therein 
fome conj^d:ures of his about the Confiftence of the Matter of 
Precious StQoes, and the Subjects wherein their chief vertues 
refide 5 he comprifes the fubftance of all in thefe tm particu- 
lars ; F/r/?,That many of thefe Gems,and the Medical Stones, 
either were once ^«/(:/Bodies5as theTraufparent ones,orin part 
made up of fuch fubftances as were once fluid. Se^ondly^ Thskt 
many of the real virtues of fuch Stones may be probably deri- 
ved from thc^mixture oiMetalline and other mineral fubftances, 
which are ufually /though unfufpeifledly) incorporated with 
themjand that th^ greatnefs of the Variety and Efficacy of tbofe 
virtues may be attributed to fome happy concurrent circum- 
ftances of that commixture. 
The j5rj?pf thefe Heads irelateth properly to the Origine of 
Gems : the ficond^i^Axt\y to thatjand partly to the kindf and de^ 
grees oithtit virtues. 
To countenance the former,the Author alledges for his ^rfi 
Argument feyeral ConfiderationSjtaken firft from the Diaph^s 
neity of Gems i^ecojidlyj their external figuration^ thirdly^ 
their internal texture ^ fourthlyj their Colours that feem to be 
adventitious and imparted by fome coloured Mineral Juice^or 
fome tinging Mineral exhalation, whilfl the Stone was either 
