When the
pressure diminishes, the movement takes place in an opposite direction.
The tracing is done by means of a special form of style giving indelible
curves through the medium of colored glycerine. The position of the
point is determined in such a way as to annul the friction of the pen,
and consequently to give it greater sensitiveness.
It should be remarked that the course of the rod, K, is amplified in the
tracing of the ordinates of the pressure according to the ratio of the
diameters of the pulleys, N and O.
The apparatus may be carried by hand by means of the handle, S, either
in or out of its case. To put it in operation, it is only necessary to
connect the apparatus with a gas burner (located near the place where
the variations of pressure are to be observed) by means of rubber
tubing. The apparatus may be employed under the same circumstances as
glass and U-shaped water manometers, with the further advantage that the
results are registered, and consequently can be more easily compared.
* * * * *
CENTRIFUGAL APPARATUS FOR CASTING METALS.
The apparatus represented in Figs. 1, 2, 3, and 4 is the invention of
Messrs. Taylor & Wailes, and is designed for casting metallic objects
in annular form, its arrangement being slightly varied according to the
nature of the objects to be cast.
Pages:
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62