( 450 ) 
the Rain and Sno\4-water that falls in a year, to run continually 
through the whole year. 
I am well '.aware, that this deduftion is not fure ; but who can 
giveafurer? However fuch as it is, I think it is more fotif- 
faftory than a bare Negative, as is that of thofe, who pretend, it 
rains not enough to furnifli fufficient quantities of water for the 
conftant running of Rivers. 
Now then,if thefe Rain-waters are fufficient to make one River 
run, they may alfofuffice for all the reft in proportion, confi- 
deringefpecially, /^'T?, what remains for wafte, which is fuper- 
abundant 5 andfeco^dl^, what little fpace I allow to both fides 
of the River's courfe, which is but of one league on each fide. 
For, Rivers are not commonly two leagues near one another. 
It may be objected, that there are Countries vphere it raim but 
feldom, and [omewhere it rains not at all ^ and yet there are con fi- 
der able Rivers J But I anfwer , that the Rivers of thofe Coun- 
tries, where it rains but feldom , do not run continually , being 
only big in Winter, but in Summer almoft quite dried up. The 
reafonof both nhich effects is, that they being near fomehigh 
Mountains whence they come , the Snow that falls in abundance on 
thofe Hills, and is melted afterwards, is able, as long as that water 
Jafts, to make them run abundantly in Winter, leaving them dry 
when it ceafes in Summer. 
As for the Countries where it rains not at all , there are but few 
of them in the W^orld» The torrid Zone (where that may be more 
true than any where elfej is a Climat abundantly moiflned with 
Rains twice a year, and it may be more than thefe Northern 
Countries, at leaft in greater plenty at certain Seafons* But if 
there fliould be any Countries where no Rain at all fhould fall, 
that will not hinder the runningof Rivers there , becaufethey 
may have their fources in other Countries where it rains , as the 
Nile in Egjft^ v^^here it rains not, 
A Letter of the Ingenious Mr, Jeflfop of Broomha! in York-lLire, 
containijig a further account of Damps in Mines , fromifed in 
l^umb.iij.of thefetraffs. 
S I R, 
IN order to give lAr.EojIe and you fome fatisfaftion to your laft 
Letter, I went to Wingerfmrth this laft week: That which I 
faw was little, becaufeagreat parrof the Pit was filled up; but I 
found two of the Colliars in the Pits adjoyning , who had been 
fcorched 
