Viewing page 49 of 212

This transcription has been completed. Contact us with corrections.

14. 

available the work of expansion.

Two sizes of chamber were used, one 1/2 inch diameter, and one 1 inch diameter. The inside and outside diameters of the smaller chamber, Fig. 6(a), were, respectively, 1.28 cm. and 3.63 cm. The nozzle, polished until very smooth, was of 8 degrees taper, and was adapted to permit the use of two extensions of different lengths. The length of the chamber, as the distance [[underlined]] l [[/underlined]] in the figure will be called, could be altered by putting in or removing cylindrical tempered steel plugs of various lengths, held in place by the breach block. Fig. 7 is a photograph of the chamber, with the nozzle of medium length in position. Fig. 8 shows the same, taken apart; and Fig. 9 shows the chamber [[strikethrough]] s [[/strikethrough]] with the medium nozzle replaced by the long nozzle.

Two small chambers were used, practically identical in all respects; one of soft tool-steel, and one of best selected nickel steel gun-barrel stock, treated to give 100,000 lbs. tensil strength, for which the writer wishes to express his indebtedness to the Winchester Repeating Arms Company.

The charge of powder, [[underlined]] P [[/underlined]], Fig. 6, was fired electrically, by a hot wire in the following way: A fine copper wire, [[underlined]] w [[/underlined]], 0.12 mm. diameter, passed through the wadding, Fig. 6(b), consisting of two disks of stiff cardboard, and this copper wire joined a short length of platinum or platenoid wire of 0.1 mm. diameter, [[underlined]] f [[/underlined]], extending across the inner part of the wadding, in contact with the powder. To the other end of this platinum wire, a short length of the copper wire passed to the side of the wadding, and made electrical contact with the wall of the chamber. A fine steel wire, [[underlined]] W [[/underlined]], 0.24 mm. in diameter, served to pull the copper wire, [[underlined]] w [[/underlined]], tightly enough to prevent