234 “SF. Peckham on a new apparatus 
rendered were very imperfect. To obviate this difficulty, I made 
the orifice beneath the valve only one-sixteenth of an inch in 
diameter, the surface of the orifice being to that of the retort as 
one to sixty thousand. This arrangement enabled me to secure 
a constant flow of vapor from the retort, to maintain a constant 
pressure, and to preserve a eonstant degree of temperature. 
found by computation that a pressure of two ounces avoirdupois 
upon an orifice one-sixteenth of an inch in diameter was equiv- 
alent to a pressure of forty pounds to the square inch, yet when 
laced a weight of two ounces upon the spindle, which of 
itself weighed half an ounce, the steam gauge registered only 
ten pounds, and the oils passed through it unchanged in density. 
Although I employed one of the most skillful workers of brass 
in this city to grind the valve, I am satisfied that the fault was 
ticity of the spring incident to the high temperature of ‘the 
vapors of the oil. I am convinced that the amount of this dimi- 
upon them, to which are carefully fitted strong brass eaps. 1 
Upper cap should be about three-quarters of an inch in thick 
ness Perforated two-thirds through from the inside with 2 
a drill, the orifice to serve as a guide to the upper end 
of the spindle. There should be a nipple three-fourths ofan 
7 in length upon the lower cap, to conneet it with the retort 
Cap ! about one-half an inch in thickness, and 
passage of poe The valve rtself should be 
upon the end of asp 
