Page:Popular Science Monthly Volume 91.djvu/929

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Popular Science Monthly A Telephone Conversation May Be Almost "Private" Nowadays

A SILENCER which is easily attached to the ordinary telephone makes it possible to talk into the transmitter without being overheard by any one in the same room.

The silencer is provided with a tube and a dia- phragm to increase the vibrations. This is so effective that even a whis- per may be heard. At the speaking end is a pliable rubber mouthpiece that fits closely over the lips. Sanitary mouth- pieces for the purpose come in nests so that fre- quent changes are possible.


the piston cylinder. Every square inch of piston area gives a hundred-pound push to the piston rod. Since the resulting force is again multiplied by levers on the top of the riveter, it is no won- der that so mighty a pressure is obtained.

The "reach" of the ma- chine is twenty-one feet. By turning the pair of plates around, therefore, girders over forty feet wide can be joined.

The reenforcing of the joints of this riveter was something of a problem. The tension at the base joint amounts to nearly three hundred tons. The heavy toggle joint shown, The mouthpiece entirely incloses however, withstands even the mouth so that no sounds escape this tremendous pressure.

���Another Biggest Thing in the World This Time a Riveting Machine

THE largest riveting machine in the world has been brought out by an engineering company of Chi- cago. Aside from its giant propor- tions (it will take the widest girder ever made) the machine is capable of driving a rivet home with blows each exerting a pressure of a hundred tons.

The machine is mounted vertically. This enables a pair of girders to be fed through with the greatest facility. An overhead traveling crane carries two overlapping plates into the machine. The vertical line of bolts which are to join the plates together are then riveted one by one as the crane moves the gir- ders either up or down.

The pressure ex- erted upon the bolt heads makes the seam steamtight. Com- pressed air under a '• pressure of a hundred pounds to the square inch is admitted to

��The U.

���The giant riveter which does at one hundred pounds

��Marconi Company Sues the S. Government for $1,000,000

THE Marconi Wireless Telegraph Company of America has filed in the Court of Claims a petition against the United States, claiming that the Govern- ment, through the War and Navy Departments, and also the Department of Commerce, has unlaw- fully been constructing and using since June 25, 1910, wireless telegraph instru- ments which infringe upon their patents. Some of the patents involved date back to the be- ginning of practical wireless telegraphy. The Marconi Com- pany charges that the damage amounts to a million dollars, and ac- cordingly, is suing the Government for that prodigious sum.

Interest in the case I; is increased by the multiplied uses to which wireless 1 appa- its work ratus is being put at

pressure this particular time.

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