Selections from the Additions That Have Been Occasionally Annexed to the Nautical Almanac; From Its Commencement to the Year 1812

Selections from the Additions That Have Been Occasionally Annexed to the Nautical Almanac; From Its Commencement to the Year 1812

List price: US$14.14

Currently unavailable

Add to wishlist

AbeBooks may have this title (opens in new window).

Try AbeBooks

Description

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1813 edition. Excerpt: ...it was really astonishing to see how much better the metal turned out, being considerably harder than before, and incomparably less porous. I mention this circumstance, which any one may easily try, to shew the very great advantage of using a small portion of arsenic to render it more compact, and, as Sir Isaac Newton justly observes, more white than before. The use of the small portion of brass in this composition is to render it more tough, and not so excessive brittle, as this composition without the brass would prove. A small portion of silver will make the metal much whiter, though if too much is added it is apt to be porous. Having said so much relative to the composition of the metal, which indeed is a capital Article, I pass on to See appendix to Gregory's optics, p 219; or the Philosophical Transactions, No. Si. HE MAJTlfBS OF CASTISO THE METAL. The sand most proper for casting this, and indeed any other metal, is a fine sand, with no more loam or clay mixed with it naturally than is absolutely necessary to make it tenacious enough to adhere together when properly moistened. If too much clay is mixed by nature with the sanck it will always blow the metal in different directions, sometimes indeed to the great danger of the operator. On the contrary, if the sand does not contain a sufficient quantity of clay, it will not remain in the flasks, or take a proper impression from the pattern or model. The best sand I could ever meet with for the purpose of casting specula, is the common Highgate sand (near London) generally used by the London founders. It should be as little wet as may be, and well beaten, but not too hard. The flasks should be at least two inches wider than the metal intended to be cast. If the sand is not of a sufficient...show more

Product details

  • Paperback | 38 pages
  • 189 x 246 x 2mm | 86g
  • Rarebooksclub.com
  • Miami Fl, United States
  • English
  • black & white illustrations
  • 1236523067
  • 9781236523068