It will be seen that by this system two of the sides of the parallelogram are capable of elongating or contracting through the unwinding and winding of the silken thread on the drums of the two cog wheels, which latter, gearing with each other, allow of the escape of but the same length of the two threads.

It will be observed that in this system integration is effected by forcing the pen to follow a certain direction, and that consequently the curve does not depend upon the dimensions of the different parts of the apparatus.—­La Lumiere Electrique.

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APPARATUS FOR MANUFACTURING GASEOUS BEVERAGES.

The apparatus represented in the accompanying cuts is designed for the manufacture of gaseous beverages, and is of Messrs. Boulet & Co.’s make.  Fig. 1 represents the apparatus complete, with gasometer and bottling machine.  Fig. 2 gives a vertical section of the apparatus properly so called, including the producer, the purifier, and the saturator, all grouped upon a cast-iron column.

[Illustration:  Fig. 1.  Apparatus for manufacturing gaseous breezes.]

The producer, A, is designed to receive the sulphuric acid and carbonate of lime.  A mixer, F, revolves in the interior of this, and effects an intimate admixture of the lime and acid without the necessity of the former being pulverized beforehand.  The carbonate of lime (usually in the form of chalk) is introduced directly into the producer through the aperture, K, while the acid contained in the receptacle, B, at the side of the column and above the producer flows put through a curved pipe in the bottom.  The flow is regulated by the valve, C. The receptacle, B, is lined with platinum.  As soon as the acid comes into contact with the carbonate, there occurs a disengagement of carbonic acid gas, which flows directly through the pipe, F, into the purifier at the upper part of the column.  From thence the gas passes into a third washer, D, of glass.  When thoroughly washed, it flows through the pipe, L, into the gasometer, which is of galvanized iron, and is very carefully balanced.

The saturator, which is the most important part of the apparatus, comprises a pump, a feed reservoir, and a sphere.  The pump, which is of bronze, is placed at the side of the column, at the lower part (Fig. 1).  This sucks up the gas stored in the gasometer and the water contained in the reservoir, and forces them into the sphere.  This latter is of bronze, cast in a single piece, and the thickness of its sides prevents all danger of explosion.  It is silvered internally, and provided with a powerful rotary agitator that favors the admixture of the water and gas.

[Illustration:  Fig. 2.]

The apparatus it rendered complete by a bottling machine, which is placed either on a line with the apparatus or in front of it.  This machine is connected directly with the sphere by a block-tin pipe.—­Chronique Industrielle.