File:Annual report of the Regents (1900) (14799101873).jpg

Identifier: annualreportof5421900newy (find matches)
Title: Annual report of the Regents
Year: 1889 (1880s)
Authors: New York State Museum University of the State of New York. Board of Regents
Subjects: New York State Museum Science
Publisher: Albany : J.B. Lyon, State Printer
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Biodiversity Heritage Library

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31^ of waterto mix it up. The air shrinkage was less, being only 6.5^, and thetensile strength was 20 pounds a square inch. At cone 9 the totalshrinkage was 15^ and the color whitish. In the Deville furnace atcone 34 the clav remained unaffected. 790 NEW YORK STATE MUSEUM The mecitamcal analysis is: Clay substance 92. 50 Snt 2.30 Yery fine sand .80 Fine sand 4. 60 100.20 A sample of tlie better grade fire clary from tlie present largeopening was likewise tested, as it represents a common type of clayfound on Staten Island. This was far more plastic than the other two; it had a tensilestrength of 45 pounds a square inch. 30^ of water gave a workablemass, whose air shrinkage was 8.25^. When burned to cone 12the color was yellowish white and the total shrinkage 17^. The clay did not fuse at cone 30 in the Deville furnace; so thatit can be properly classed as a fire clay. The mechanical analysis gave: Clay substance 70 Silt 7 Yery fine sa.nd 7 Tine sand 14 98 o C3 o a«t-i o tHtH I—<
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bi 3o s 2 -:: >> w - -1 a a ■^ >. r •/. - o ? 0) ^, ;^ .ti i:i 0. a; ;:2 Z ft p 8- 5 a C3 irt ^ B ei •ti -I IS f a * 3 d V .-1 a> 55 > CO o a A to a « A p Oi ^ ft >> S o a 0) S 5 CLAYS OF NEW YORK 791 POTTEKY The term pottery is properly applied to such articles for domesticor ornamental use as can be turned on a potters wheel. While thiswas the original method of forming such wares, in the progress ofthe art many other methods have been devised, which, in somecases, have superseded the potters wheel, though this useful ma-chine is still employed to a large extent. Description of different grades The more important grades of pottery which are recognized arequite numerous. Earthenware. This is the lowest grade of pottery, and is usuallymade from medium or poorer grades of clay. The body is eitherred or buff, and more or less porous. Earthenware vessels will nothold liquids unless glazed, owing to their porous nature. Thecom

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