laft of them fiiews the Sum both of rhe hall Ounces 
that have fallen during that fpace of time, and the 
height the Water would have been i aifed ia that time 
alfo. To this I fliall only add one Example : Tlie Sum 
of all the Rain in the Teo firft Years 41 217, and there- 
fore according to what hath been faid, 4i2x[7isthe 
number of half Pounds that fell in compafs of the Tun- 
nel during thofeTen Years; and 4i2[x7 the height it 
would have raifed the Water during that time. But if 
you defire to be more critical, if you add i[o6 its loorh, 
part, you will have ^i^l'^y for the true height, and 
4 1 [4 1 3 for the mean height by thofe Ten Years Ob» 
fervations; and ^l^[^7 for the mean quantity ef half 
Pounds. By the fame Method you will have the means 
for the other Five, viz. of tieight 4i[78, and 4i7[S 
for the mean number of half Pounds, which means do 
ftrangely agree, and both cor^fidered do give for the 
mean by all the Fifteen Years 4i[5'i6 Inches in height, 
which is about | of an Inch more than double to that 
raifed by the Water at Paris^ which as fet down in the 
Memoirs for the Ingenious, for Fehruary Jaft, is ftated 
about 19 Y French Inches, which make %\ EvgVtjh, 1 
have omitted the Account of the Years 87 and 88, 
which I found faulty, by reafon the Perfon ( who had 
the charge of noting what Rain fell during my abftnce 
feveral times then from home ) did nor punQuilly ob- 
ferve rhe ufual Method I had prefer ibed him. I forgot 
when I mentioned my way of Gauging by Weight, that 
it was grounded upon z%[yi6i Cubical Inches of Rain- 
water, being equal in weight to one Pounds or i % Ounces 
Troy ; fo that dividing any Superficies in Inches of a 
Veflel for receiving the Rain-water by the before men- 
tioned Number, it will give you the Pounds and Parts 
that will raife the Water upon that Superficies, with up- 
right fides, juft an Inch: And thus I found that 4[974 
Pounds would fill a Cylinder equal at the bottom to my 
