TEE WORLD'S ADVANCE 



9 



closely simulated. It is exceedingly sim- 

 ple, consisting of a tin scoop with a 

 capacity of a half gallon and a loop of 

 stout rubber tubing which can be at- 

 tached instantly to any bath tub. 



To operate the rowing bath, the bather 

 seats himself in the tub, throws the rub- 

 ber loop over the faucet of the tub and 

 turns on the cold water. As it pours into 

 the tub he scoops it up in generous quan- 

 tity and dashes it upon his chest. Be- 

 cause of the resistance offered by the 

 rubber attachment, the muscular 

 effort may be made as easy or as 

 difficult as one desires, and it is 

 easily possible to work up gen- 

 erous perspiration even though 

 the temperature of the water is 

 low enough to be uncomfortable 

 were the bather absolutely idle. 



clock swings with such precision that 

 after 576,000,000 seconds (more than 

 eighteen years) the error of the clock 

 is only one second. 



A HOME-MADE TRACTOR 



A traction engine made from parts 

 of an old gasoline motor, some old gears 

 and wheels from binders and other odds 

 and ends found in a barn, is used by a 



PERFECT TIMEPIECES 



An astronomical clock must keep more 

 nearly perfect time than any other in- 

 strument. The makers of such clocks 

 must consider how much effect slight 

 changes in the temperature and in the 

 pressure of the air will have upon the 

 oscillation of the pendulum. There have 

 been prepared elaborate tables that show 

 the weights of dry and moist air at vary- 

 ing temperatures and atmospheric pres- 

 sures. 



There is a Riefler clock at Potsdam in 

 which virtually all the influences that 

 affect the swinging pendulum, no mat- 

 ter how minutely, are compensated for. 

 The pendulum of this astronomical 



Two Views of a Traction Engine that 

 was Made from the Parts of an Old 

 Gasoline Motor, Some Old Gears and 

 Wheels from Binders and Other Odds 

 and Ends. 



young Canadian farmer to do the chores 

 of his neighbors within a radius of sev- 

 eral miles of his home. The motor is 

 connected by chain drive to the two rear 

 wheels, and on a good road the tractor 

 can move at a comfortable speed. Its 

 construction, although crude and cum- 

 bersome, is quite ingenious. 



Mr. Dempster, who was probably the 

 first man to ride a bicycle in England 

 and who was also a distinguished elec- 

 trical engineer and scientist, died re- 

 cently at Schenectady. It is claimed that 

 he also built the first commercial tele- 

 phone in England in 1876. 



