( ) 
.as large, 'yet by all .the Tryals I have made, very Jittle 
Light appears, tho’ in the darkeO: Room 5 and the heft 
time ot making thefe Experiments, is when the Sun is i 3 
Degrees below the Horizon 5 and when the Sun is fo, tho* 
the Moon Ihines never fo bright, the Light is the fame as 
in the darkeft Room, which makes me chufe to call it a 
No&iluca. 
I will not prefume to give you my Thoughts concern- 
ing Amber, (which Teems to be a Receptacle, and an in- 
exhauflible Treafuie of Eighty) why upon a hardfridtion 
rile Light rhould, as it were, be ftrain’d out of fuch a num- 
ber of places? Nor why upon an eafie fridion it fhou’d 
not give thofe Cracklings and Light, unlefs the Finger, 
or Tome other Body, be held at a little diftance from it ? 
Nor why in a dark Room, tho’ it Crackles, it (hou’d give lit- 
tle or no Light till the Sun is near down ? But I have men- 
tion’d thefe few things, amongft many others, to fee 
if I cou’d provoke you, Sir, to give me your Thoughts 
about them, not knowing any one fo capable of doing 
it as your felf: And the Friendfhip you have al- 
ways profefs’d tome, makes me hope you’ll be pleas’d to 
excufe this irregular account of my Obfervations, for you 
have ’em in the fame order juft as I made ’em. ! 
As the Artificial Fhofphorus led me to that of Amber, i 
fo Amber direded me to that of a Diamond^ from its be- j 
ing Eledral as well as the other, which is alfo a Natural j 
Phofphorus, or rather a No^iluca, exceeding all others, and 
may, without any Exception, be call’d a Mineral ■ 
phorus, it being, as I think, the moft pure of all ’ 
fums^ coagulated with a Mineral Acidum^ and if in ■ 
the Difeovery of this I have not oblig'd the Learned, I’m 
in hopes I (hall all thofe who deal in Diamonds 5 for none 
of the many I have talk’d withal know any thing of the 
Matter 5 tho’ Mr. Boyle has given the World an Account, 
at the latter end of his Book of Colours, of Mr. Claytons 
Diamond, 
