[Illustration:  FIG. 7.]

[Illustration:  FIG. 8.]

Proof is therefore given that the soda engine has a working capacity which is at least equal to that of the coal burning engine.  The heating surface of the soda engine, moreover, is 85 square meters, while that of the corresponding new Henschel engine is 92 square meters.  On a former occasion I have already stated that the soda engine is capable not only of performing powerful work and of producing a large quantity of steam during a short time, but also of travelling long distances with the same quantity of soda.  Thus, for example, a regular passenger train, with military transport of ten carriages, was conveyed on Nov. 6, 1884, from Aix la Chapelle to Julich and back, i.e., a distance of 45 kilos, by means of the fireless engine.  The gradients on this line are 1 in 100, 1 in 80, and 1 in 65, being a total elevation of about 200 meters.  For a performance like this a powerful engine is required, and a proof of it can be recognized in the consumption of steam during the journey, for the quantity of water evaporated and absorbed by 41/2 to 5 cubic meters soda lye was 6,500 liters.

Another certificate concerning the tramway engine illustrated in Figs. 5 and 6 is of equal interest, and runs as follows: 

Aix la Chapelle, Jan. 5, 1885.

A fireless soda engine, together with evaporating apparatus, has been at work on the Aix la Chapelle-Burtscheid tramway for the last half year.  In order to test the working capacity of this locomotive engine, and the consumption of fuel on a certain day, the Honigmann locomotive engine was put to work this day from 8:45 o’clock a.m. till 8 o’clock p.m., with a pause of three-quarters of an hour for the second quantity of soda lye.  The engine was, therefore, at work for fully 101/2 hours, viz., 51/2 hours, with the first quantity, and five with the second.  The distance between Heinrichsalle and Wilhelmstrasse, where the engine performed the regular service, is 1 kilo, and there are gradients

Of about 1 in 30 in 400 meter length.
   " 1 " 45 " 250 "
   " 1 " 72 " 350 "

This distance was traversed sixty-four times, the total distance, including the journeys to the station, being 66 kilos.  The engine gives off fully 15-horse power on the steepest gradient, the total traction weight being 81/2 to 9 tons; it is worked with an average steam pressure of 5 atmospheres, and has cylinders of 180 mm. diameter and 220 mm. stroke, cog wheel-gear of 2 to 3, and driving wheels of 700 mm. diameter.  The quantity of water evaporated during the service time of 101/2 hours was found to be about 1,600 kilogs., consequently about 800 kilogs. steam was absorbed by one quantity of soda, the weight of which was ascertained at about 1,100 kilogs.  The averaging heating surface is 9.8 square meters; the difference of temperature between soda lye and water was toward the end only 3 deg.  Cent.; 234 kilogs. pitcoal were used for boiling down the lye for the 101/2 hours’ service, which corresponds to a 6.6 fold evaporation.