22 ACCOUNT or tue SPRAY 
parts of the neighbouring rocks: when thefe are dathed in 
pieces it is evident that the {pray which they contain bet- 
ween their layers mult be broke off and fcattered about. 
To this may be added that travellers who colle& pieces of 
this {pray as they go along generally throw away what 
they have gathered when they meet with other fragments 
which are larger or pleafe them better: hence we often fee 
this fubftance at fome diflance from the rocks, and in places 
where otherwife it would be difficult to account for its be- 
ing found in. 
Several. attempts have been made to afcertainthe height 
of thefe Falls at different times and by different perfons; 
but their accounts have varied from 138 feet to 174. 
Upon an attentive view it evidently appears that the ftra~ 
ta of the rock over whichthe river is projected are inclined 
tothe plane of the horizon: this is diftinQly feen in the 
land which divides the Fall into two parts. It is likewife 
very certain that a much larger body of water comes down 
the South-Weft channel than down the North-Eaft one. 
From thefe confiderations I began to fufpe&, that the 
height of the South-Weit fide was lefs than that of the 
North-Eaft; and fuppofing this to be the cafe it account- 
ed eafily for the variety in the different meafurements. 
To afcertain this point, I, inthe year 1781, undertook te 
meafure both fides, in company with the ating engineer. 
The firft attempt which we made was by trigonometry, 
but in the execution of this we found many difhiculties from 
the great inequality and ruggednefs of the rocks. I even 
{ufpeéted that the rays of light pafling through the medi- 
um of a thick mift, might fuffer more or lefs refraCtion, 
and occafion a deception in the angle taken. As we had 
previoully determined to meafure them in every poflible 
manner, we next proceeded to let a cord down with a 
{mall weight hung to it. From the inequality of the rocks 
at the bottom, it was impoflible to let thecord quite down, 
We, 
