[ 8 ! J 
a Light on this obfcure Subject. I am, with very 
great RefpeCt, 
‘Dear Sir , 
Tooting, Feb. 15,' Tour faithful Friend , 
1745-6. 
and obliged humble Ser vant, 
H. Miles. 
XVII. An Account of a Book intituled. \ De 
quamplurimis Pholphoris nunc primum 
detedlis Commentarius. AuSlore Jac. Bar- 
thol. Beccario. Printed in 4.1:0. at Bo 
lognia, 1744. RxtraEled and tranjlated 
from the Latin by W. Watfon, F. R. S. 
Read Feb. 27. r I ‘HE ingenious Author, in the Work 
> 745 - • before us, does not treat exprefly 
of thofe Productions of the chemical Art, which we 
ufually call Thofphori, but principally of fuch Sub- 
ftances, whether natural or artificial, which imbibe 
the Rays of Light in fuch Quantities, and in fuch a 
Manner, as to appear luminous for a Time, even in 
abfolute Darkneis. 
Before I enter upon the Subject -Matter of this 
Treatife, I mult take notice of the Apparatus made 
life of in thefe Inquiries. Our Author caufed a 
wooden Box to be made, large enough either to lit in, 
or Hand in upright; yet not fo large but he might 
with Eafe be carried to any Place the molt convenient 
L for 
