For the generation of sulphurous acid Dr. Bruno Terne, of Mass., has constructed a very simple apparatus shown in Fig. 40. The sulphur is burned in S; A is the escape pipe of stone; T, the collecting reservoir; P, the steam-pump for acid; R, chimney for the sulphur burner.
4. CONVERSION OF CARTILAGE INTO GLUE.
The conversion into glue of the swollen cartilage obtained by treatment with hydrochloric or sulphurous acid may be effected by continued boiling in open pans or in an apparatus recommended by Wm. Friedberg, and shown in Fig. 41.
The boiler K of thick boiler-plate has a diameter equal to its height. Underneath the perforated false bottom S, which serves for the support of the bones, lies a perforated steam coil R—D for the introduction of steam. To this steam coil is fitted a branch-pipe d, which reaches into the upper portion of the boiler into which also enters the water-pipe W. The apparatus is further fitted with a water-gauge, an air cock, sampling cock and manhole for the introduction of the cartilage.
Fig. 41.
The mode of operation with this apparatus is as follows: The boiler is filled three-quarters full with cartilage. Enough water to fill the boiler one-quarter full is then admitted through the pipe W, and the steam-cock D opened. The steam passing out through the numerous perforations in the coil R, is at first condensed in the water, but soon brings the latter to the boiling-point, and from this stage on begins the formation of glue. The glue dissolves in the water, and a sample of the solution is from time to time drawn off through the sampling cock and tested as to its concentration. When the solution possesses the required concentration, the admission of steam through R is interrupted, and the cock d of the branch-pipe opened, as well as the cock of the discharge pipe H, the latter being opened gradually. The discharge pipe H is connected with the perforated plate F, which is covered with a closely-woven cloth and thus acts as a filter, retaining all the solid particles suspended in the glue solution.
By opening the cock d of the branch-pipe, the steam-pressure acts only upon the surface of the fluid, the latter being consequently pressed with great force through the filter-cloth.
When the hissing noise caused by escaping steam indicates that all the fluid has been removed from the boiler, the cock d of the branch-pipe is closed, and through a rose fitted above the boiler, water is allowed to flow upon the latter. By this cooling the greater portion of the steam in the boiler is condensed and water may be admitted through W.
Fig. 42.