IMPROVEMENTS IN THE MANUFACTURE OF COLOURED OR TINTED GLASS GLOBES, SHADES, OR REFLECTORS, AND OF COLOURED OR TINTED GLASS FOR OTHER PURPOSES
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by Rice Williams Harris at the Office of
the Commissioners of Patents on the 4th July 1882.
RICE WILLIAMS HARRIS of 107 Rue de Provence, Paris, in the Republic of France
"IMPROVEMENTS IN THE MANUFACTURE OF COLOURED OR TINTED GLASS GLOBES,
SHADES, OR REFLECTORS, AND OF COLOURED OR TINTED GLASS FOR OTHER
PURPOSES
"
This invention relates more especially to the manufacture of coloured or tinted
glass globes, shades and reflectors for Electric lighting or other illuminating
apparatus, but it is also applicable to the production of tinted glass for other
purposes.
The object of the invention so far as regards the production of glass globes,
shades or reflectors for electric lighting and other illuminating apparatus is to
obviate as much as possible the loss of light which takes place when globes,
shades or reflectors of the ordinary coloured tinted or frosted glass are employed,
and at the same time to retain such a tint in the glass as shall change the
objectionable cold dazzling light (in the case of the electric light) into a soft yellow,
rose coloured or other tint which shall not fatigue the eye. And further to
economize the cost of such globes shades or reflectors.
By the ordinary methods of producing yellow glass, for example, the required
tint cannot be obtained except at a considerable cost which renders globes shades
or reflectors made of it, too expensive for general consumption. Heretofore this
colour has only been obtainable by colouring the mass with silver either in an
oxidized or reguline state or by staining the article after it has been finished. In
the first of these methods the colouring material is too costly, in the latter a
second operation is required. A cheaper yellow can be produced with carbon or
wood bark but the colour is too black, yellows can also be made with Uranium but
they are expensive and show a whitish green tint:
By my improvements I obtain a perfect yellow of any required depth of colour,
and at a cost little exceeding that of the ordinary plain globe or shade. My
improvements consist in the following method of manufacture. A ball of flint
glass is gathered from the pot, on the end of a tube, while the glass is in a state of
fusion, this ball is then covered with one or other of the colouring compositions

page_text: hereafter described which adheres to it, it is then reheated. In the meantime a
cup of glass is formed with an aperture in the bottom thereof to allow of the escape
of the air or gases produced by the ignition of the colouring matter. The ball of
glass with the colouring matter on its surface is placed in this cup and the whole
welded together and blown to the required shape.
The colouring compositions above referred to are composed as follows:-
For transparent colours I take the ordinary pigments employed in the external
decoration of porcelain which are fired in an oven at a low temperature, to these I
add a
"fret" or "base" composed of sand, oxide of lead potass, and antimony.
This fret is melted in a crucible, run into water, dried, and pounded to as fine a
powder as possible. This powder is mixed with the aforesaid colouring matter,
and the surface of the ball of. hot flint glass is covered with this mixture before it
is inserted in the cup.
For opaque colours I employ the same kind of pigments as for transparent
colours, and I add to them a "fret" or "base" composed of sand, oxide of lead,
nitrate of potass, subcarbonate of potass, oxide of tin, arsenic and fluorspar. This
fret or base is used in the same manner as in the case of the transparent colours.
In the fret or base for semi-opaque or opalized colours in place of the oxide of
tin I employ phosphate of lime, and in the fret or base required for Rose or
Ruby colours, white or carbonate of lead must be employed in place of the red
oxide.
•
Attempts to employ the above mentioned ordinary pigments for the purpose of
colouring or tinting glass have failed because the said pigments are burnt or
vapourized by the heat of the semi-fused glass but by combining them with the
powdered materials above specified previous to their application to the heated surface
of the glass their use is rendered practicable and easy.
By the use of the process and materials above described I am enabled to supersede
casing or flashing, thus avoiding all risk of cracking, only one kind of glass being
employed, besides which many other advantages are obtained, for example. 'Economy
in material, expensive compositions and combinations being avoided, a pot of
ordinary glass being all that is requisite. Economy in labour, one man only being
required where two are usually employed, an ordinary workman being able to do
the work as well as an expensive one. Economy in pots and consequently in fuel,
as one pot of white glass suffices instead of having to discolour and employ several
simultaneously a regular tint is always ensured by this method of manipulation.
The colour can be applied to any kind of glass in any description of melting
furnace, either crystal or common glass serving the purpose equally well.. There is
no chance of cracking, only one kind of glass being employed in the manufacture.