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. 



913 



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. 



