SAND-BLAST (ante), a method of engraving, cutting, and boring glass, stone, metal, or other hard substances,, by the percussive force of a rapid stream of sharp sand driven against them by artificial means. The process was invented by gen. Benj. C. B. Tilgh man, of Philadelphia, who took out a patent for it in Oct., 1870. In the world of nature the abrading power of sand when driven by air or water against hard substances has long been recognized, and gen. Tilghman's invention was merely an application of this principle to the mechanical arts. The means of propulsion mily be supplied either by an air oz a steam blast, the former being,produced by a boiler at high pressure, and the latter by a an revolving with great velocity. In either case the abrading material, which is usually common hard sand, although small granules of iron or crushed quartz are occasionally used, is directed by a tube upon the object to be cut or engraved, the latter being so adjusted by means of slides that each part in succession can be brought under the action of the cutting particles. The engraving of the surface of glass with ornamental figures, etc., may by this process be very easily accomplished simply by'lay ing upon it patterns of the desired objects cut out of some resistant medium in the man ner of stencils. The sand, of course, does not touch the protected parts, but indents tho§e which are uncovered, until the result sought for is attained. Another method very commonly used is to cut the proposed pattern in sheet copper or brass, which is then placed over the glass, a brush of melted' beeswax being drawn over the whole. The stencil is then raised, and the pattern left in exposed glass may then be operated' upon by the blast. The ornamentation of glass in colors may also be performed by the sand-blast, for as the ordinary colored glass of commerce is mere window glass, with a thin layer of color on one side only, the use of the stenciled pattern as before will entirely remove the color from the exposed parts and leave it where pi'sotected. By the use of a photographed coating of gelatine upon glass (the well-known gelatine proc ess in photography) very beautiful reproductions of line engravings may be made upon the glass at a small cost. The sand-blast has also been used successfully iu the cutting of ornaments and inscriptions upon stone. Iron stencils are sometimes used for tine
purpose, but the most patisfactory material is fotual to be sheet rubber of about 1-16th of an inch in thickness. This is cemented upon the-stone and a movable pipe is caused to traverse the surface of the latter until the exposed portions have been suffi ciently abraded. The wear upon the rubber itself is wonderfully slight and the same stencil may be-used over and over again. Another use to which the sand-blast lms_heen successfully put is in turning blocks of stone into circular and other forms in the lathe.
i Balcony pilasters, etc., have in this way been finished in a few hours which would have needed as many days to be cut out by hand. Upon wood the action of the sand-blast is not so satisfactory, being slow and tedious, and the only way in which it can be utilized on this material is in cutting out the large block type used in printing posters. The foregoing are only a few of the ways in which the sand-blast has manifested its useful ness, but as the Invention is still in its infancy it is impossible to say what applications may not be found for it in the future. From its fist appearance the sand-blast has attracted Much -attention both at home and abroad, many foreign patents have been taken out, and the use of the process is gradually spreading.
is a splitting or fracture of the horny fibers of the horse's hoof, extend ing usually from above downward; when reaching to the quick it causes lameness, and in all cases it constitutes unsoundness. Horses with thin, weak, brittle feet, spoilt by much rasping, and rattled on the hard roads, furnish the majority of cases. The horn must be thinned for an eighth of an inch on either side of the crack; across the upper and lower ends of the crack, to prevent its extension, the firing-iron should be drawn, mak ing a line nearly through the horny crust. The openin; may further be held together by winding round the foot several yards of waxed string, or fine iron wire. Except in very bad cases, slow work on soft land may be permitted, but road work' is inju rious. • The growth of healthy horn is promoted by applying round the coronet, at intervals of 10 days, some mild blistering liniment.
See LAUNCE.