It will be seen from the diagram that the quantity of air taken into the cylinder and the compression pressure remain constant with any load, and that for this reason it is possible to have a constant point of ignition, or rather point of fuel injection. As there is no mixture compressed, there are no difficulties encountered at light loads due to attenuated mixtures. An excess of air over that required to burn the fuel is also present at every load within the range of the engine. For the sake of simplicity, the suction and scavenging lines on the Diesel engine have been omitted, but they are the same in all respects as the corresponding lines shown in the diagram, Fig. 14. (40) Gas Turbine Development. In the attempt to gain mechanical simplicity, small weight, and diminutive size of the steam turbine, many able experimenters have endeavored to obtain an internal combustion motor in which the energy of the expanding gas is converted into mechanical power by its reaction on a bladed wheel, but so far the problem is far from being solved. In 1906 two experimental turbines were built by René Armengand and M. Lemale, of the constant pressure type, one of which developed 30 Brake horse-power and the other 300 horse-power. A 25 horse-power De Laval steam turbine was altered by Armengand says Dugald Clerk so that it operated with compressed air instead of steam. The compressed air was passed into a combustion chamber together with measured quantities of gasoline vapor, and the mixture was ignited by an incandescent platinum wire as it entered the chamber, thus maintaining a constant pressure with continuous combustion. Around the carborundum lined combustion chamber was imbedded a coil in which steam was generated by the heat of the burning gas, the steam being used to reduce the temperature of the gas from 1800°C to about 400° as it issued from the orifice and came into contact with the running wheel. The working medium was therefore composed of two elements, the products of combustion and the steam at the comparatively low temperature of 400°C. The constant pressure maintained in the combustion chamber was about 10 atmospheres, and the hot gases were allowed to expand through a conical Lava jet in which the expansion produced a high velocity, and reduced the temperature of the fluid. At this reduced temperature and high velocity the gases impinged upon the Laval wheel, and rotated the wheel in the same way as steam would have done. The experiments showed that under these conditions the total power obtained from the turbine separate from the compressor was double that necessary to drive the compressor.