337 



This feature of cleanliness opens up a new objection to the present 

 form of serimeter, emphasizing as it does the variability in the time 

 necessary for the weights to descend in the different official serimeters 

 of the world. 



Qaajaf s Horizontal Serimeter. 



Desiring therefore to construct a serimeter that would overcome this 

 difficulty, M. Quajat has designed that shown in Fig. 76. This apparatus 

 is horizontal instead of vertical as is usual. It is handier to use and the 

 operator can employ it with less fatigue. 



It is composed of two pieces placed upon a base which may be leveled 

 by an adjusting screw. The piece A carries a iiendulum a which draws 

 with it in its movement the pointer h which, as in other dynamometers, 

 marks on a quadrant the number of grams by which it has been dis- 

 placed. To a small clip, c, is attached one end of the filament to be 

 tested. This piece is so placed that its level will be as little disturbed as 

 possible during the test. A small stop piece, d, holds the end of the pen- 

 dulum at the zero of the scale and at the same time shows whether the 

 apparatus is level. 



On the piece B the second end of the filament is caught in the clip e, 

 which is exactly 50 centimeters from the clip c when all the pointers 

 are at zero. The pointer/ runs along a scale divided into millimeters 

 and shows exactly the distance which the thread has stretched when 

 rupture takes place. The movement of the pointer is caused by means 

 of a driving screw, g, which is turned by a crank which is connected to 

 it through a pair of miter gears, and which has such a pitch that the 

 movement of the hand will advance the pointer 10 millimeters per 

 second. The nut/ is so constructed that it may be detached by a single 

 turn of the screw /t, which throws it out of gear with the driving screw 

 and enables ns to bring it back to the zero point.* 



The mode of compensation for the movement of the clip c is exceed- 

 ingly simple, the pendulum being so adjusted that it will displace that 



* This descriptiou is translated from the pamphlet already mentioned. The cut is 

 also reproduced from it. 



