Mr Watts'* ObservUtimis on tJbe Resistance Fluids. $15 
swelled to such a size as I fear must have exhausted the patience 
of many of your reader s, must subscribe myself^ 
Very truly yours, C. Daubeny. 
Magd. Coll, Oxfoed, 
Aet. XI . — Observations on the Resistance of Fluids. By 
William Watts, Esq. Communicated by the Author, 
The effect of the deep immersion of bodies in water, still 
remains a contested point in the theory of the resistance of 
Fluids; and many persons are of opinion, that the resist- 
ance increases with the depth, although the experiments of 
Sir Isaac Newton, made with small globes formed of wax, 
having lead inclosed in them, and made so light as to weigh 
only a few grains in water, in order that they might descend 
very slowly in this fluid, seem to prove that the resistance 
is equal in every pojrt ; for these globes having been let fall m 
water ^ descended in the same manner as they would have de- 
scended in a fluid in which the resistance was every where equal, 
though, when they were near the bottom of the vessel, the com- 
pression was many times greater than when they were near 
the top. 
This supposed increase of resistance at greater depths, is 
even assumed as a principle by Mr Gordon^ in his Theory of 
Naval Architecture ; but the grounds of this assumption do not 
appear to be satisfactorily explained ; and this is not to be won- 
dered at, if we consider that a competent knowledge of the mu- 
tual actions of fluids on each other, is accessible only to those 
who are intimately acquainted with all the refinements of the 
modern analysis, and that, without this key, there is no admit- 
tance into this department of the physico-mathematical sciences* 
These observations, however, do not apply to the investiga- 
tion of Don George Juan d’Ulloa, who, in his Examine 
Maritimo^'" has attempted to consider the subject in a scientific 
manner, and has given some important experiments, similar to 
