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. 1891 Excerpt: ...the Author has been the Engineer throughout. The communication is accompanied by four photographs and a plate, from the latter of which the Figs, in the text have been prepared. APPENDIX. Concrete In The Superstructure. The concrete used in the superstructure above the reef deposited out oi water was composed of 3 parts broken slag, J of gravel, 1 of sand, and 1 of cement (see the Table below). All these materials were measured separately in a dry state before being mixed. Large lumps of slag were added to, and incorporated with, the concrete after it was deposited in place, to the extent of about one-sixth of the whole mass. The Author found in practice that with these proportions he obtained the utmost quantity of finished concrete--having a matrix consisting of equal parts of sand and cement--consistent with the making of perfectly solid work. The same proportions did not produce a concrete suitable for deposit below water, there being too much broken slag to admit of making solid work in places where the concrete could not be manipulated with a shovel after deposit. The following data relating to this concrete were also obtained. The materials in the above proportions when dry measured 5,431-69 cubic inches (see Table below). After being mixed and turned over three times dry, and three times after 394-27 cubic inches of water were added, they produced a finished block of concrete measuring 3,133 cubic inches, or 57"68 per cent only of the bulk of the dry materials. While, in the dry materials, the proportion of all other materials to the cement is as 4J to 1, in the finished block thia propor tion becomes 2-7 to 1; and the proportion of the finished concrete to the cement used is 3-2 to I. The reduction in bulk, and tho difference in the proportion of c...