In the case of posts the compression between the collars is communicated to the four points on the arms by means of brass rods; with short blocks, as in Fig.

33, the points of the arms are in direct contact with the collars.

The operator lowers the fulcrum of the apparatus by moving the micrometer screws at such a rate that the set-screw in the rear end of the upper lever is kept barely touching the fixed arm below it, being guided by a bell operated by electric contact.
_Log of the test_: The load is applied continuously at a uniform rate of speed.

(See SPEED OF TESTING MACHINE, above.) Readings are taken from the scale of the compressometer at regular increments of either load or compression.

The stress-strain diagram is continued to at least one deformation point beyond the maximum load, and in event of sudden failure, the direction of the curve beyond the maximum point is indicated.