The most important points of contact between Ericsson's work and these advances were in connection with his introduction of the surface condenser, the use of artificial draft, devices for heating feed water, his studies in superheated steam and its use, and his work in connection with the development of the compound principle in steam-engines, his relation to the introduction of the screw-propeller, and to the use of twin screws at a later time.

The economical use of such a reflector or intensifier would require that all energy supplied to an air condenser should be recoverable, or, in other words, that there should not be any losses, neither in the gaseous medium nor through its action elsewhere. This is far from being so, but, fortunately, the losses may be reduced to anything desired.

Under any circumstances, whether the air pump is working or not, a certain percentage of the vapor in the condenser is always carried down the pipe B, and this action alone creates a partial vacuum, thus rendering the work of the air pump easier.

As has been previously pointed out, the successful and satisfactory operation of the turbine depends very largely on the condenser.

No particular advantage was, however, gained by this method, except in cases where the currents from the condenser were large and the keeping cool of the surfaces was necessary, and in cases when, the discharge not being oscillating of itself, the arc as soon as established was broken by the air current, thus starting the vibration at intervals in rapid succession.

It required, indeed, the greatest attention, and three hands were constantly employed in filling up the boiler and supplying the condenser with cold water.

This morning, to my great joy, about nine o'clock, the surface of the moon being frightfully near, and my apprehensions excited to the utmost, the pump of my condenser at length gave evident tokens of an alteration in the atmosphere. By ten, I had reason to believe its density considerably increased.

The Operation of the Key Circuit. The effect in a C. W. transmitter when a telegraph key is connected in series with a buzzer and a battery and these are shunted around the condenser in the grid circuit, is to rapidly change the wave form of the sustained oscillations, and hence, the length of the waves that are sent out.

Then it is led to the big condenser downstairs, where the final power is added, and the condensed light is stored. "Quartz conducts light just as copper conducts electricity those are bus bars we saw running around there. "The bombs we've been meeting recently are, of course, little knots of this light energy thrown out by that projector mechanism we saw.

The Rotary Spark Gap. In this type of spark gap the two fixed electrodes are connected with the terminals of the secondary coil of the power transformer and also with the condenser and primary of the oscillation transformer.