Per Cent.
Caffeine.2.710
Theobromine.0.084
Bitter principle.0.018
Total alkaloids.———2.812
Fatty matters:
Saponifiable fat or oil.0.734
Essential oil.0.081
Total oils.———0.815
Resinoid matter (sol. in abs. alcohol)1.012
Sugar:
Glucose (reduces alkaline cuprammonium).3.312
Sucrose? (red. alk. cupram. after inversion)[1].0.602
Total sugars.———3.914
Starch, gum, etc.:
Gum (soluble in H2O at 90° F.).4.876
Starch.28.990
Amidinous matter (coloring with iodine).2.130
Total gum and fecula.———35.999
Albuminoid matters.8.642
Red and other coloring matters.3.670
Kolatannic acids.1.204
Mineral matter:
Potassa.1.415
Chlorine.0.702
Phosphoric acid.0.371
Other salts, etc.2.330
Total ash.———4.818
Moisture.9.722
Ligneous matter and loss.27.395
———
100.000

Both the French and German governments are introducing it into their military dietaries, and in England several large contract orders cannot yet be filled, owing to insufficiency of supply, while a well-known cocoa manufacturing firm has taken up the preparation of kola chocolate upon a commercial scale.—W. Lascelles-Scott, in Jour. Soc. Arts.

[1]
Inverted by boiling with a 2.5 per cent. solution of citric acid for ten minutes.

CHAPIN WROUGHT IRON.

By W.H. SEARLES, Chairman of the Committee, Civil Engineers' Club of Cleveland, O.

Notwithstanding the wonderful development of our steel industries in the last decade, the improvements in the modes of manufacture, and the undoubted strength of the metal under certain circumstances, nevertheless we find that steel has not altogether met the requirements of engineers as a structural material. Although its breaking strain and elastic limit are higher than those of wrought iron, the latter metal is frequently preferred and selected for tensile members, even when steel is used under compression in the same structure. The Niagara cantilever bridge is a notable instance of this practice. When steel is used in tension its working strains are not allowed to be over fifty per cent. above those adopted for wrought iron.

The reasons for the suspicion with which steel is regarded are well understood. Not only is there a lack of uniformity in the product, but apparently the same steel will manifest very different results under slight provocation. Steel is very sensitive, not only to slight changes in chemical composition, but also to mechanical treatment, such as straightening, bending, punching, planing, heating, etc. Initial strains may be developed by any of these processes that would seriously affect the efficiency of the metal in service.

Among the steels, those that are softer are more serviceable and reliable than the harder ones, especially whereever shocks and concussions or rapidly alternating strains are to be endured. In other words, the more nearly steel resembles good wrought iron, the more certain it is to render lasting service when used within appropriate limits of strain. Indeed, a wrought iron of fine quality is better calculated to endure fatigue than any steel. This is particularly noticeable in steam hammer pistons, propeller shafts, and railroad axles. A better quality of wrought iron, therefore, has long been a desideratum, and it appears now that it has at last been found.

Several years since, a pneumatic process of manufacturing wrought iron was invented and patented by Dr. Chapin, and an experimental plant was erected near Chicago. Enough was done to demonstrate, first, that an iron of unprecedentedly good qualities was attainable from common pig; and second, that the cost of its manufacture would not exceed that of Bessemer steel. Nevertheless, owing to lack of funds properly to push the invention against the jealous opposition which it encountered, the enterprise came to a halt until quite recently, when its merits found a champion in Gustav Lindenthal, C.E., member of this club, who is now the general manager of the Chapin Pneumatic Iron Co., and under whose direction this new quality of iron will soon be put upon the market.