APPENDIX TO CHAPTER LIV.----SHRINKAGE, ETC. 411 of the mold into a chill or all-iron mould. This is split in halves, as will be noticed, and a ring clamp, as at B, is used to hold it firmly together, E being a bottom block for the chill proper to rest on, and D a funnel cap placed loosely on the top of a chill to insure the stream of metal being guided directly into the chill mould without any being spilled. Before pouring these moulds they are tested to learn if their cubic contents for holding metal are exactly alike, by means of filling one with fine hour-glass sand, and then pouring the same into the other. This is done only as a precaution, to make sure that no extra thickness of blacking or distortion of the dry sand mold has occurred in any manner while making it. There are three of these dry sand moulds made for each cast or test of any one grade of metal, two being called portable and one stationary. The plan of using these moulds is as follows : A portable mould is secured in the ladle shank and the small cupola (page 241) tapped to fill it direct, and it is then quickly poured into the chill mould as TAliLK 86.—SHRINKAGE AND CONTRACTION OF GRAY AND CHILLED IRONS. Meat Nos. i 2 3 4 5 6 Character of metal tested. Ferro-silicon. Foundry iron. Bessemer iron. 15",' steel with gray iron Charcoal iron. Charcoal iron. Silicon .................. 12.25 1-75 1.72 1.6 1 •75 .70 Sulphur.. ......... .021 .04 .054 •055 .03 •035 Shrinkage of chilled iron 3 ox. 240 gr. 2 OX. 240 gr. 2 OK. i So gr. 2 OX. 290 gr. 6 ox. 6 oz. 280 gr. Shrinkage of gray iroti 3oz. I 07,. 2iogr. I O'/,. 140 gr. I OX. 460 gr. 2 OH. 120 gr. Contraction of chilled iron... .270" .262" .271" .322" .446" .460" Contraction of gray iron .24 " .205" .111" .227" .229" .235"