( 730 ) 
lingt of Steel, mtb the aJmiJfton of a little Water, mil 
not only caufe a great Ejfervefcence, but will of it felf 
Break forth into an a^ual Fire ; I (aid exprefly , a little 
Water; becaule toomnch Water will hinder the Operati- 
on, or quench the Fire. Which I take to be the Cafe of 
the Bath-Waters, where Steel and Sulphur caufe a great 
EfFervefcence, but no Flame. And the like of other 
Hot Springs. And I do not confine it to this particular 
Mixture ; for the Chy«iifts, I prefume, may furnifh 
us with divers others. And therefore I faid, or fome- 
what equivalent. But I gave Inftance of this for 
one. 
I would have added alio, That the fame Account may 
be given of /Stna (and other burning Mountains-) 
where the Mixture of Steel and Sulphur may give a 
Flame ; which is oft attended with prodigious Explofi- 
ons (and Earth-quakes) from great Quantities of Niter, 
as in fpringing a Mine, 
I fliall alfo take this Occafion to redify fome Num- 
bers which I find to have been miflaken in my Treati(e 
of Algelra, at Cap. 109. which though they do not 
vitiate the Demonftration (which will hold as well when 
thefe be reftified) yet I think fit to corredl them, that 
they may not give the Reader a trouble. 
In Algelrce mes Cap. CIX. irrepferunt l^umeri vitioji. 
Qui quamvis fummam Demonjtrationis non evert ant ^ funt 
tarn re£lificar^?ii. Propojitum eB^ Datum Cuhum ( cujus 
latus ponatur =15) it a per for are, ut Cubus alter, ipfi 
aqualis, per foramen tranfeat. Quod cum plurihus modis 
fieri pojfiti hunc felegis. InteSigatur Cuius perforandus, 
Sphane infer iptus ; Cujus itaq; Diameter feu Axis erit 
(j^qualts Diagonio Cuhi) 3 . Cujus Polos occupent 
Cult Anguhs A, & huic oppofitus latens. Reliquiq: fex 
Anguli 
