Year: 1886

page_text: We, SERAFINO ANTONIO CALDERARA and ALFRED JAMES CALDERARA both of
No. 10 Cross Street, Hatton Garden, in the County of Middlesex, Meteorological
Instrument Makers do hereby declare the nature of our invention to be as
follows:-
n
A glass hydrometer as it is usually made, consists of a glass bulb blown having
a tubular stem in which is enclosed the scale, and having at the bottom a small
bulb containing mercury by which its load is adjusted. In blowing the bulbs of
those instruments it is difficult or almost impossible to make them of the exact
bulk desired or uniform in bulk and consequently the scale for each has to be
adjusted by actual, trial.
i 3
'
Now according to my invention I provide a mould in which the bulb is blown,
the exact bulk and displacement being thus determined. by the volume of the
mould. I am also enabled to give the bulb a form not only circular in section
as they usually are, but also elliptical, square or of other shapes in transverse
section, and conical, pyramidal or otherwise in vertical section. Having, by thus
blowing in a mould, secured uniformity in bulk or displacement of the bulb, I can
apply to this bulb stems of various dimensions to suit the various scales that may
be required.
:

page_text: We, SERAFINO ANTONIO CALDERARA and ALFRED JAMES CALDERARA both of
No. 10 Cross Street, Hatton Garden in the County of Middlesex Meteorological
Instrument Makers do hereby declare the nature of our invention and in what
manner the same is to be performed to be particularly described and ascertained in
and by the following statement :-
A glass hydrometer as it is usually made, consists of a glass bulb blown having
a tubular stem in which is enclosed the scale, and having at the bottom a small
bulb containing mercury by which its load is adjusted. In blowing the bulbs of
these instruments it is difficult or almost impossible to make them of the exact
bulk desired or uniform in bulk and consequently the scale for each has to be
adjusted by actual trial.
=
: .
Now according to our invention we provide a mould in which the bulb is blown,
the exact bulk and displacement being thus determined by the volume of the
mould. We are also enabled to give the bulb a form not only circular in section
as they usually are, but also elliptical, square or of other shapes in transverse
section, and conical, pyramidal or otherwise in vertical section. Having, by thus
blowing in a mould, secured uniformity in bulk or the displacement of the bulb,
we can apply to this bulb stems of various dimensions to suit the various scales
that may be required.
Fig. 1 of the accompanying drawings is a side view and Fig. 2 is a plan shewing
a blank of a hydrometer bulb of square section as it is blown in a mould, Fig. 3
shewing the hydrometer in its complete form. Fig. 4 is an elevation and Fig. 5 is
a plan shewing another form of bulb. The blank Fig. I is blown inverted like a
bottle or phial in a mould of the desired form. It has a closed conical end a and
a tubular neck b. The end of the cone a being cut off, the tube of any required
length is fused to it; also the tubular neck b is either closed by the blowpipe and
blown into the form of the mercury bulb d, or, preferably, the neck b is cut and
narrowed in at e and a bulb d separately blown is fused to it. Afterwards the
bulb d receives its adjusted charge of mercury. The bulb shewn by Figs. 4 and 5
is also blown in a mould and has the tube o fused to it. The loading of the bulb
is in this case effected by introducing a number of small heavy objects such as shot
along with sealing wax or other readily fusible cementing material, which, being
melted sets, holding the shot together as one mass f. Instead of loading the bulb
in this manner, an alloy fusible at a low temperature may be introduced. It is
preferred to make the bulbs of the square form such as is shewn in Figs. 1, 2 and 3
or of the form shewn in Figs. 4 or 5, or of other forms presenting projecting angles,
wings or ribs, because these projections impede the rotation of the bulb in the
liquid, such as often occurs with bulbs of circular section, rendering it difficult to
observe the graduated scale in the tube a.

page_text: Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is :-
The construction and use of glass hydrometers having their bulbs blown in
moulds of the size and shape desired, substantially as and for the purposes act
forth.
Dated this 16th day of November 1886.
ABEL & IMRAY,
Agents for the Applicants,
28, Southampton Buildings, London, W.C.