DESCRIPTION or a MACHINE, &c. 239 
have been the confequence, This isa plain indication of 
its narcotick quality, and ftupefactive powers. 
Ue... Cae 
Defcription of a Machine for meafuring a /fhip’s way: in 
a letter from Francis. Hopkinson, Esq. to Mr. 
Joun VAUGHAN.. 
Read Dec. Y N the 2d. volume of our Philofophical Tranf- 
*7) "79° ff actions, I publithed a defcription of an inftru- 
ment for meafuring a thip’s way through the fea. I have 
not heard of any. objection: to the principles on which 
fuch a machine may be conftruGed,. but it may, probably, 
have been thought too complex for general ufe. 
As this obje&t, fhould it be accomplithed, would be of 
great importance, I have made. another attempt to the 
fame purpofe; in which, if there fhould be no other ob- 
jeQtion, the want of fimplicity cannot reafonably be com- 
plained of, 
Clofe along the fhip’s bow is a copper pipe, about two 
inchesin diameter, extending downwardas low as the keel, 
and upward above the water line when the veffel is load- 
ed. ‘This pipe muft be fo bent. at the bottom as that. it’s 
orifice may be dire€tly oppofed to the line of. the fhip’s 
progrefs, and project but.a little way beyond the keel or 
cut-water. The upper part of this pipe muft alfo be fo 
bent as that it may enter into the fore-caftle, through a 
hole made for the purpofe, above the water line. The 
pipe fhould be fecured in its place by ftaples or clamps. 
On the top of this copper pipe fhould be a cover to be 
{crewed on, and through the cover a hole mult be made 
for 
