(1) One four-inch wrought iron pipe, eighteen inches out to out, with usual thread on each end. At about nine inches from either end this pipe is drilled and tapped for a one-inch nipple, in such a manner that a pipe introduced would pass, not on a line with the radius, but about half way between the axis of the four-inch pipe and its walls; in other words, it would be on a line with a chord of the circle. (2) One one-inch wrought iron nipple, two inches long, one-inch thread on one end. (3) Two four-inch malleable iron caps, drilled and tapped for a one-inch pipe. (4) One one-inch wrought iron pipe, twenty-four inches out to out, with a three-inch straight thread on each end. (5) Two one-inch iron caps. A hole, one-eighth of an inch in diameter, is drilled in the end of one of these caps. The above order can be given _literatim_, and will be understood by the dealer, who will furnish, at a trifling cost, the materials, cut and tapped as ordered. Fig. 1 shows how the whole is put together. The numbers on the figure correspond also to the numbers of the paragraphs of the order as given above. [Illustration: FIG. 1.] [Illustration: FIG. 2.] Fig. 2 is an end section. A cork is inserted in 2 and through it a thermometer, the bulb of which is on a level with the interior pipe. The whole is supported on a few bricks at either end, and is kept steady and in place by a couple of weights or half bricks. It is heated by one or two Bunsen burners, according to the temperature desired.--_Jour. Fr. Institute_. * * * * * TESTING CEMENT.