96 PROCEEDINGS OF THE AMERICAN ACADEMY 



6. There is an objection to this form of stuffing box, inasmuch as 

 at very high pressures the threads aaaa and bbhh tend to act as lock- 

 nuts on each other. To obviate this annoyance I devised the method 

 shown in Figures 9 and 10. Here the thread aa is movable, being on 

 the inside of a ring, rr, of steel, which fits snugly in a socket of the 

 barrel. The ring rr, though cajDable of moving back and forth, can- 

 not rotate, being prevented by the projection s, corresponding to a 

 slot in the barrel. In this way the material in the stuffing box is not 

 forced into the barrel on actuating KK. Note that the thread within 

 KK is carried quite to the end, and that the inner face of KK is 

 bevelled very obliquely, thus allowing the gasket to encircle a greater 

 number of threads of the screw SS. The strain is now borne by the 

 thread hb. Experiment has shown this to be no disadvantage. 



7. Barrel. Body. — This is perforated by four or more holes 

 (Fig. 1), about § inch in diameter, and threaded to admit the tinned 

 machine screws. Two of these, MM, are vertical, the other two, 

 N^ (Fig. 4), horizontal. They are of use in filling the barrel with 

 oil, for attaching gauges and other appurtenances. 



8. Barrel. End loith Piezometer Tube.* — These steel tubes, ZZZJZZ, 

 are inserted in such a way as to insulate them electrically from the 

 barrel end CC. A screw is cut on the end of UUU, fitting into a 

 cast iron flange, WW, between two cylindrical jackets, XX and YY, of 

 hard rubber or ivory. These parts Y, W, X, are screwed to the end 

 of the tube V, and the cylinders l^and X axe turned large enough to 

 fit the hole of the barrel and the internal aperture of the steel nut ZZ 

 snugly. All space within the head CC is filled with marine glue, dd. 

 This is easily accomplished by melting the cement into the crevices 

 between Tand W, Ifand X, before putting the piezometer in place. 

 A thick gasket, dd, is also inserted. After this the remaining annular 

 space around W, through which leakage might occur, is filled by for- 

 cing in the nut ZZ gradually, and at a temperature not too low.f To 



* "Welclless cold drawn steel tubing of any dimension may be obtained from 

 John S. Leng, New York, or of Philip S. Justice, Philadelphia, U. S. A. Both 

 gentlemen are agents of English houses whose address is not known to me. 



t The figure is somewhat diagrammatic here to exhibit the parts. In practice 

 I use hard rubber cylinders XX and YY, and two hard rubber annular disks be- 

 tween yi'and WW, and WW and XX, respectively. When ready for inser- 

 tion, the cylinders are screwed against W W, so tliat there are mere films of 

 marine glue left between contiguous planes. Finally, the nut ZZ is brought in 

 contact with the flange of YY (disk) by pressure. It is in view of the fact that 

 YY is pressed radially inward toward the axis of UU, as well as outward by 

 pressure, that the arrangement holds so well. Repacking is only rarely neces- 



