Page:Popular Science Monthly Volume 91.djvu/575

 Popular Science Monthly

��Joininq of layers applied at different times

��plastering-like method in which a very dense but fluid mixture of cement is shot into place by means ,of compressed air. The former type is the most common and may be made with or without double-bottoms, or with single or dual hulls separated by an air space which may or may not be employed to carry fuel or water ballast. Both types of con- struction are shown in the accompanying perspective and de- tailed sketches.

���How the Ships Will Be Built

The method by which the concrete is shot into place by means of compressed air as advocated by Carl Weber, a con- crete engineer of Chicago, is really an adaptation of the "cement gun" process previously described in the Popular Sci- ence Monthly. This

method makes use of a light steel frame- work for the vessel. To this framework are attached a series of re-enforcing rods carry- ing wire mesh or other flexible re-enforcing, each of which is., in turn covered, by thin layers of concrete forced against one another in the applying so that the whole is a ho- mogeneous mass of such a nature that the line of joining one layer with the next cannot be detected if the slab is cut across. The details of all of these methods are shown in the ac- companying il- lustrations.

The great ad- vantage of the compressed-air method of shoot- ing the concrete inio place, is that it eliminates al- most one-half of the wood or steel forms necessary if the ordinary pouring method is pursued. This

��The T-irons, spacer bars, hooked rods and wire mesh of a shot-into-place concrete boat are shown. The three vertical lines between the ragged lines indicating the wire mesh show roughly the thickness of each layer

��559

��is an important advantage because of the first cost of the forms; their difficulty of construction due to the unusual shapes at the extreme front and rear ends of the vessel and the cost of setting up the forms and moving them from point to point on the vessel after they have been re- moved from sections already poured and hardened. The advocates of the pouring method have planned to over- come the difficulty and cost of moving the forms by devising a cheap, steel frame- work both inside and outside of the vessel along which the forms may be pushed with- out lowering them to the ground.

Unusual-shaped forms for the forward and rear ends of the ves- sel may be provided by the use of collapsi- ble steel forms such as are used in bridge culvert work.

��Vertical mesh holding rods

��Spacer bar

FratjisversesecTion ugh concrete

��"•'"" hull I st layer 2 n<J layer 3 rd and last layer

A Section Through the Side

���The Chinese ambulance, veyance in which pigs

��Clang! Clang! Make Way for the Chinese Ambulance

ONE of the reasons why the people of the Occident are generally disposed to agree. with Bret Hart that "the heathen Chinee is peculiar" is the unusual method of the Chinese in handling the sick. Notice the ambulance in the photograph, in which a dying man is being transported. It is of wicker basketry of the same type as that used for conveying pigs and poultry to market.

Crude as this type of convey- ance seems, no rubber-tired automobile could travel with less jolting. The car- riers work in re- lays, going slowly, with a kind of swing, and rest-

��It is just like the con- are taken to market

��ing at intervals.

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