USRE3095E - Improvement in mxbking-slates - Google Patents

Description

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HENRY W. HOLLY, OF BROOKLYN, NEW YORK, ASSIGNEE OF JOHN W. HOARD, OF PROVIDENCE, RHODE ISLAND.

Letters Patent No. 16,687, dated February 24, 1857; reissue No. 3,095, dated August 25, 1868.

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Specification of an Improvement in the Manufacture of Artificial Slates for Marking or Writing,-app1icable also to other purposes, the invention of JOHN W. HOABD, of the city and county of Providence, in the State of Rhode Island. I

This improvement in the preparation or manufacture of artificial slates or tablets, and other like'articles formal-king or writing upon, consists in the use of liquid quartz or silex, and in combining with. the same ari oxide asa di'ying, anti-deliquescent, and coloring-substance, and in which connection it will suflice here only to specially refer to the oxide of zinc as the anti-deliquescent and coloring-substance employed. Likewise, the invention covers in aslate, tablet, or slated surface, of the description mentioned, subjecting the same before fully dry to a calen'dering process or roller-pressure for the purpose of obtaining a finer and harder finislrto saidsurface.

The following is one mode in which said invention may be carried into practice:

Take liquid quartz made in any suitable manner, and which may be as described in works on chemistry,

such, for instance, as found in Knapps Chemical Technology, pages 147, H8, 149, vol. ii, published by Lea & Blanchard, Philadelphia, 1849, and evaporate it to the consistency of thin cream.

To make a white sheet, slate, or tablet for writing or marking upon with a graphite pencil, it is preferred to mix with such soluble quartz three times its weight of the white oxide of zinc, and afterwards to knead these two substances rapidly together into a paste that may be spread on a sheet of pasteboard of the size designed for a slate or tablet, and the whole afterward run between a pair of smooth rollers to give a finer and harder finish to the surface when dry. In about twenty-four hours'this soluble glas s paste on the pasteboard is dry enough for use, if exposed to a temperature of about 60 Fahrenheit, and is found toadhere tenaciously to the pasteboard, forminga hard, smooth coating, or beautiful slate or slated surface for marking or writing upon with, say, an ordinary lead-pencil.

To make colored slates for marking with a slate or othorpencil, alike process of manufacture may be adopted, only substituting forthe white oxide of zinc any suitable coloring-substance or substances.

If desired, a colored paste may be put on one side of a sheet of pasteboard and a white paste on the other side thereof, thus forming a slate for writing-or markingwith two kinds of pencils; or said slate may be only coated 'on one side. I i I Said paste, fol-producing artificial slates or slated surfaces, maybeputpn wb'od, iron, and other materials or bodies, instead of pastcboard. It makes a very superior substitute for common blackboards in academies and schools, and the same may be put on to the surface or body designed to be cover'ed by it with albrush by,

say, diluting it to the proper consistence, which may be done Withwater, applying said diluted paste, and allowit to dry in successive'coats, or said paste may be otherwise applied and spread.

By using an oxide with the liquid quartz, the artificial slate or slated surface is made anti-deliquescent, or more indurate, and different colors given to it, according to the color of the oxide employed, or other coloringmatter may be substituted or added. Aslate or tablet, blackboard, or other article of card or sheet-like character for marking or writing upon, may thus be produced by simply spreading the liquid quartz, or same combined with an oxide, to the thickness and consistency required, upon sheets of wood, iron, pasteboard, paper, or other suitable material, the same presenting a hard and fine slated surface ready for marking or writing upon by pencil, chalk, or other marker, with every facility for erasure by the application ofmoisture or rubbing.

What is here claimed, and desired to be secured by Letters Patent, is'

1. Theuse of liquid silex in the preparation orman'ufacture of artificial slates, tablets, blackboards, and 1 other like articles for markin or writin u on.

2. The combination of an oxide asa drying, anti-dcliqucscent, and coloring-substance, with liquid quartz or silex, as a mcnstruum in the manufacture of artificial slates, substantially as specified.

3. An artificial slate or tablet, formed by spreading liquid quartz or silex, either separate or mixed with other materials, on a suitable surface or body, of card or sheet form, and, prior to being dried, ealendering or rolling the same under pressure, essentially as herein set forth.

HENRY W. HOLLY.

Witnesses:

HENRY T. Buows, A. H. Jocsnrs.