US295137A - wittmaiw - Google Patents

Description

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UNITED STATES ATENT nnion;

RUDOLF O. VITTMANN, NEV YORK, N. Y., ASSIGNOR TO HIHS'ELF AND CHARLES NELSON, OF SAME PLACE.

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SPEIZEIICTION forming part of Letters `Patent No. 295,137, dated March 11, 1884.

Application filed July 18,1863. (Model.)

Be it known that I, RUDOLF C. VVLTTMANN, a citizen of Austria, residing at New York, in the county and State of New-York, have invented new and usei'ulIinproVenientsinVVriting-Tablets, of which the following is a specication.

This invention relates to an artificial slate or writing-tablet; and it consists in a tablet or sheet of pasteboard, Wood,`or equivalent material having' a layer of White cement applied to its opposite sides, as Will fully appear from the following specification, reference being had to the accompanying drawings, in which- Figure 1 represents alface View of my iniproved slate or Writing-tablet, and Fig. 2 a section of the same.

In carrying out Inyinvention I prepare a White cement by moistening pnlverized magnesia with asolution of chloride of magnesium, and of this nioistened mass I' place a tbin layer into a mold of the desired size, and then place upon said layer a piece oi thin Wood, pasteboard, muslin, or equivalent material, and on this intermediate layer I place a layer of the meistened mass or cement and submit the whole to pressure. Instead of magnesia-cement, other White cement may be nsed-snch as a cement prepared from lime, sand, and pulverized iiint.

The slate or writing-tablet prepared as above described can be provided with lines or copies, such as numbers, letters, or sentences, to fa cilitate the operation of Writing` properly and neatly; and, if desired,l suitable pigments may be added to the cement before forming slates or tablets, so as to impart to the same any desired color.

rEhe lines, letters, or copies are produced by printing the saine upon the surface of the slate or tablet in a color contrasting to that of the slate or tablet. The printing can be combined with the operation of pressing the slates or tablets,- or may be' performed rafter the same have been pressed. i

Referring to the drawings, A indicates a slate or tablet made in the manner above described. b indicates the foundation-sheet, of pasteboard, wood, or equivalent material, and c c the layers of cement applied to its opposite sides.

l. A artificial slate or Writing-tablet composed of two layers of cementsuch as inagnesia-cement-and an intermediate layer of Wood, pasteboard, or equivalent material, sub stantially as described.

2. An artificial slate or writing-tablet -niade of White cement, and having imprinted on its face or faces iines or copies, or both, in acolor different from that of the cement, substantially as described.

In testimony whereof I have hereunto set my hand and seal in the presence of two subscribing'witnesses.

E. F. KAsTnNHUBnn.

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