US 761001 A
Description (OCR text may contain errors)
No. 761,001. R PATENTED MAY 24, 1904. L. LEBATEUX.
MAGIC 0R SURPRISE PICTURE. ABPLIOATION FILED MAY 14, 1902.
3 #112216 with a 01108) coin B *Rllb with a oilver 00in I l i] 1 1 2 m'izzaadea: 112226727122" M Lou/.5 LE'BA TH/X I ar flitorney UNITED STATES Patented May 24, 1904.
P TENT OFFICE.
MAGIC OR SURPRISE PICTURE.
SPECIFICATION forming part of Letters Patent No. 761,001, dated May 24, 1904.
Application filed May 14:, 1902. Serial No. 107,276. (No model.)
To all whom it may concern.-
Be it known that I, LOUIS LEBATEUX, a citizen of the Republic of France, and a resident of Paris, in the Republic of France, have invented certain new and useful Improvements in Magic or Surprise Pictures, of which the following is a specification.
My invention relates to an improved form and method of carrying out the invention disclosed in United States Patent No. 471,305 to Tschoffen; and its object is similar to Tschoffens, being to form on paper surfaces marks or designs that are normally invisible, but that are adapted to be brought out by rubbing with certain marking materials.
In the accompanying drawings, Figure 1 ,shows the back of a postal card as it appears before being developed by rubbing, and Fig.
2 shows the same after a few strokes have been made with a coin.
A is the card. B is any suitable instruction printed thereon to indicate how the card is to be treated, and C is the magic or surprise image which appears partially developed in Tschoflfen forms the invisible design of chalk pigment applied with a gum-arabic vehicle and develops the image by rubbing with crayons or colored powders. It is to be noted that rubbing with crayons, colored powders, or the like necessarily soils the paper in places that are not covered with composition; also, that the gum-arabic on drying forms a coating of hard gum over the small particles of the pigment, and thus materially reduces the roughness and biting effect thereof.
My improvements relate to the vehicle, the pigment, and the method of application, with the object of producing designs of great deli cacy and perfection adapted to be developed by rubbing with a relatively soft metal, particularly by rubbing with a silver coin. The advantage of silver as a developer is that it leaves no trace whatever on the uncovered parts of the paper surfaces if the rubbing be light enough, and in order that hard rubbing shall not be necessary I produce an invisible image the surface of which is strongly abrasive and is especially adapted to be marked by silver. The production of such an invisible image depends upon the discovery of a suitable pigment and a suitable vehicle for applying the same. The vehicle that I use is an unctuous fluid or semifluid substance-such as ing, is mostly all drawn into the papersupport and that little, if any, trace thereof is left adhering to the pigment particles, which thus preserve their sharpness; thirdly, that it repels moisture. The pigment that I use is zincwhite. Silver rubbed on a zinc-white surface shows a line that has the firm and dark appearance of a line made with a graphite pencil Zinc-white is the zinc oxid or the zinc carbonate, and in commercial form it often contains barium sulfate. Moreover, the zinc oxid turns into the carbonate by gradual absorption of the carbon dioxid in the air. The very fine pure zinc oXid produced by sublimation is the substance that I prefer to use, because it permits of making the finest desirable lines; but the presence of the other substances named is rather beneficial, as they are even more stable and inertthan the pure zinc oxid. A great advantage of the Zinc-white is that it does not energetically unite with the oil vehicle and that any chemical changes that may occur in it do not change its color or materially affect its abrasive quality. A substance like white lead, that has a strong affinity for the fatty acids, is in great measure altered physically by the chemical actions that take place. No such action is to be feared with a pigment as inert as zinc-white. White lead would also color in the presence of certain vapors of the atmosphere, and this would prematurely bring out the image before the application of the intended developing agent. My zinc-white image is practically invisible and remains permanently so until rubbed. The intensity of the image is increased by repeated rubbing, and the maximum available intensity is controlled by regulation of the proportion of pigment and oil used. A good average proportion contains seven hundred and fifty grams of zinc-white to two hundred and fifty grams of linseed-oil. This forms a mixture of about the same consistency as the printing inks and is most easily applied by printing.
As my invention permits of producing lines and designs of exceeding purity and fineness, it is well adapted to the manufacture-of what I term safety or "guarantee papers such, for example, as bank-checks, share-certificates, and the likewhich can then be easily tested by rubbing them with a coin. My invention is also valuable in the form of postal cards with humorous surprise designs or as advertising-cards, which may be packed in with articles of food, as none of the ingredients used are poisonous.
I claim as my invention and desire to secure by Letters Patent 1. An'article of manufacture consisting of a paper surface having thereon a substantially invisible design or marks produced with zincwhite.
2. An article of manufacture consisting of a paper surface having thereon a substantially invisible design or marks produced with a Zincwhite pigment rubbed up with an unctuous Vehicle.
3. An article of manufacture consisting of a paper surface having thereon a substantially invisible design or marks produced with zincwhite rubbed up with linseed-oil.
In witness whereof I have hereunto set my hand in presence of two witnesses.
LOUIS LEBATEUX. Witnesses:
HENRY A. BERTIE, EDWARD P. MAOLEAN.