TESTING CEMENT.

Otago Witness, Issue 1819, 1 October 1886, Page 22

TESTING CEMENT.

A party of gentlemen assembled at Mr James M'Donald's lime works on Wednesday afternoon to witness a test of the building cement which is now being extensively manufactured at these works. Among those present were several architects, engineers, and contractors specially interested in the subject, including Messrs R. A. Lawson, BoWini, and Ussher, also Messrs Gore and Fergus, M.H.R's. The mode adopted of testing the strength- of the cement was ingenious and extremely conclusive. The attention of the visitors was first drawn to a single row of bricks placed face to face and jutting out at right angles to the factory wall, at a height of some sft from the ground. These bricks had been placed in position one by one during the last few weeks, the cement which joined each to the preceding one being allowed to dry before the next brick was added. The row had been continued until it cons-ifited of 24 bricks, but the fall of some material from an upper storey had broken off eight, and there were 10 remaining for the visitors' inspection. The breakage, it was noticeable too, had not occurred in the cement, which held as fast as ever, but one of the bricks had been split in half by the blow. Further experiments were then made, under MrM'Donald's direction, with thiß unsupported row of 16 bricks. On the extremity of the row loose bricks were piled one

by one until the number had reached 33, meaning a weight of over 2cwb, and it was not until the addition of the thirtyfourth brick that the row beneath broke away from the wall. The strain thus stood by the cement was really extraordinary; and it was further seen that once more it was not the cement itself that had given away, but part of the brick face of the wall that had been torn down. The next test was made with a pile of 24 bricks which had been cemented together and were' lifted perpendicularly by a wire loop passed through the cement joining the topmost brick to the remainder. This loop was fastened to a pulley aud the whole pile raised into tho air, the cement joining the first two bricks thus supporting the whole weight of the others. Twelve more bricks were subsequently slung on to this burden, and the cement stood the test I perfectly. The remarkably good quality of the I manufacture was therefore demonstrated beyond the possibility of dispute.