AN IMPROVED METHOD OF AND APPARATUS FOR TESTING MILK
Year: 1881

page_text: LETTERS PATENT to Frank Wirth, of the Firm of Wirth and Company,
Patent Solicitors, at Frankfort on the Main, in the Empire of Germany, for an
Invention of "AN IMPROVED METHOD OF AND APPARATUS FOR TESTING
MILK." A communication from Friedrich Heeren, Professor and Privy
Call
Ր 1
PROVISIONAL SPECIFICATION left by the said Frank Wirth at the Office
of the Commissioners of Patents on the 25th February 1881.
FRANK WIRTH, of the Firm of Wirth and Company, Patent Solicitors, at
Frankfort on the Main, in the Empire of Germany. "AN IMPROVED METHOD
OF AND APPARATUS FOR TESTING MILK." [A communication from Friedrich
Heeren, Professor and Privy Councelor of the Government of Hanover, in the
Empire of Germany.]
This Invention relates to an improved method of testing milk and to apparatus
therefor.
In carrying the said Invention into practice I spread the milk to be tested in a
thin layer on a black or dark ground, and the color thus produced is compared with
a series of index colours painted on the apparatus hereinafter described, each of
these index colors corresponding to a certain quality of milk, thus :-(1) extremely
fat, (2) fatty, (3) good normal, (4) thin, (5) very thin.
It will be understood that I do not confine myself to the above scale, but may
form the index with any suitable arrangement of colors or degrees of shade.
The apparatus made according to my Invention is constructed as follows, viz. :-
At the centre I provide a plate of hard india-rubber, wood, or other suitable
material having a rim about half a millimeter bigh, upon which is placed a glass
plate, around which are situated the several colors forming the index.
In another form of my improved apparatus the colors forming the index are
arranged side by side, in a line and along the front of the index is situated the milk
holder with a glass plate sliding in a groove, the whole being mounted in an oblong
quadrangular frame or plate.
Another form of milk tester is constructed according to my Invention as follows,
viz.-A round plate of glass has the testing colors painted on it, the centre thereof
being left unpainted; the milk is placed under this plate and upon a dark surface,
and its color will be visible through the centre, and thus its quality can be
ascertained by comparison with one of the index colors.
It is obvious that the form of the apparatus may be varied without departing
from the principle of my Invention.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Frank Wirth in the Great Seal Patent Office on the 25th August
1881.
FRANK WIRTH, of the Firm of Wirth and Company, Patent Solicitors, at
Frankfort-on-the-Main, in the Empire of Germany.
"AN IMPROVED METHOD
OF AND APPARATUS FOR TESTING MILK." A communication from Friedrich
Heeren, Professor and Privy Councelor of the Government of Hanover, in the
Empire of Germany.
This Invention relates to an improved method of testing milk and to apparatus
therefor.
In carrying the said Invention into practice I spread the milk to be tested in a
thin layer on a black or dark ground, and the color thus produced is compared with
a series of index colors painted on the apparatus hereinafter described, each of these
index colors corresponding to a certain quality of milk, thus :-(1) extremely fat,
(2) fatty, (3) good normal, (4) thin, (5) very thin. I wish it understood that I do
not confine myself to the above scale, but may form the index with any suitable
arrangement of colors or degrees of shade or tint.
The accompanying Drawing represents two forms of apparatus constructed
according to this Invention.
Figure 1 is a plan of one form of the said apparatus, and
Figure 2 is a vertical section of the same on the line A, B, Figure 1.
Figure 3 is a plan of another form of the said apparatus, and
Figure 4 is a vertical section of the same on the line C, D, Figure 3.
In the centre of the apparatus represented in Figures 1 and 2 is a plate of hard
india rubber, wood, or other suitable material having a rim A about one half of a
millimetre high; upon this rim is placed a glass plate B, around which are situated
the several colors forming the index.
In the apparatus illustrated in Figures 3 and 4 the colors forming the index are
arranged side by side in a line, and along the front of the index is situated the
milk holder A with a glass plate B sliding in a groove.
Another form of my improved milk tester, which will be readily understood
without the assistance of a Drawing, consists of a round plate of glass which has
the testing colors painted on it but has its centre left unpainted. In using this
tester the milk is placed under the said plate and upon a dark surface, and its color
being visible through the centre of the said plate its quality can be ascertained by
comparison with the index colors.
It is obvious that the form of my improved apparatus may be varied without
departing from the principle of my Invention.
Having thus fully described the said Invention, and the manner of performing
the same, I wish it understood that I claim,-
The herein described method of testing milk by spreading it in a thin layer and
comparing its color with the different shades or tints of an index or scale of color
upon apparatus constructed substantially as above set forth.
In witness whereof, I, the said Frank Wirth, have hereunto set my hand
and seal, this Twenty-second day of August, in the year of our Lord One
thousand eight hundred and eighty-one.