A and B are used to denote respectively that the specimen was unplaned or planed. 1, 2, 3, etc., denote the number of the test made on that particular kind and condition. I., II., III., denote that the piece has been taken from a lintel, and also from what part, as will easily be seen by the accompanying sketch (Fig. 31). Thus P. B. 3 would signify that the specimen was of quality P, had been planed, and was the third test of this class. On the other hand, P. B. 3 II., would signify in addition that it had been taken from a lintel, and was a piece of one of the strips marked II. in the sketch. Loads sq. in. S. B. 3 II. Area = 0.8432 S. B. 4 IV. Area = 1.3478 P. B. 5 I. Area = 0.8778 sq. in. E. sq. in. E. E. The following is a summary of the breaking weights of the specimens not cut from the lintels : The conclusions which Messrs. Burgess and Vielé draw from these tests are the following, viz.: 1o. The tensile strength of the iron marked S was higher than that of the iron marked P. 2o. The elongations for a certain load were greater for equal areas with the grade P than with the grade S. 3°. Hence S was a stronger, but, at the same time, a more brittle iron. 4°. With the same grade of iron, the elongations were greater in planed than in unplaned specimens. 5°. The unplaned specimens in these tests had a less tensile strength per square inch than the planed. They attribute this fact to some slight irregularities in the castings, which were removed by planing. 6°. In regard to the tensile specimens cut from the lintels, it will |