Method of Modifying the Transparency of Ivory.
Year: 1895

page_text: Date of Application, 30th Dec., 1895-Accepted, 1st Feb., 1896
COMPLETE SPECIFICATION.
Method of Modifying the Transparency of Ivory.
I, CARL RASPE Manufacturer, of Weissensee near Berlin in Germany, do
hereby declare the nature of this invention and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement :-
My invention has for its object the modification or annulement of the transparency
of glassy ivory, which comes on the market in more or less thin plates and is used
for many purposes; so for instance for the belay-plates of piano-keys or knife-
handles, for fans and so forth.
The methods used so far for the destruction of undesired transparency of ivory
did not lead to satisfactory results. They were based on the intention to produce
white precipitations as phosphate of lime and the like in the gristle-substance of
the ivory, for which purpose the latter was swelled for the incorporation with salt-
solutions and the production of the precipitations.
That these attempts failed may have had as cause, that the gristle-substance did
not swell sufficiently to take up enough quantities of salt-solutions and to allow
the production of sufficient quantities of the precipitations.
My invention on the contrary to the aforesaid method is to dim the ivory
without incorporating any material into it, only by heating it throughout equally
to over 100° Cels., or 212° Fahrenh. For this purpose I prefer to heat the ivory
in a fluid, or in a mass of very fusible nature not influencing the ivory substance
chemically, as for instance: oil, paraffine, turpentine-oil and especially glycerine,
the latter because it can easily be washed off from the ivory with water after
heating.
The heating process is to be continued a more or less time according to the
condition of the ivory itself the condition of the surrounding fluid or mass and the
desired dimness,
To clean the ivory from oil paraffine, turpentine-oil or other suitable masses,
which are not soluble in water, it is of course necessary to use dissolvents of other
kinds, such as benzine or ether for instance.
To carry out my invention to dim thin plates cut out of glassy ivory to be used
for belaying piano keys, I heat these plates in one of the liquid or easily fusing
masses aforesaid in varying the temperature above 212° Fahrenh. according to the
condition of the ivory to be used, for a duration of 5 to 20 minutes, according to
the dimmes desired; then the plates are cleansed in a suitable dissolving liquid and
then bleached in a known manner.
In some cases, that is to say for some of the ivory sorts to be used, it may be
preferable to submit the plates to the bleaching process before dimming the same
as aforesaid.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare, that what I
claim is:
The method to modify or annul the transparency of ivory, which is more
transparent than desired for the application, by heating the ivory after being
surrounded by a fluid or easily fusing mass (as oil. paraffine, turpentine-oil.

page_text: glycerine and the like) having no chemical influence on the gristle substance of the
ivory, throughout equally, to more than 212° Fahrenh. as herein before described.
Dated this 28th day of December 1895.
CARL RASPE,
By his Agent,
F. H. Haase.