760 



SCIENTIFIC RECREATIONS. 



tions of the hour-tube. A reflector placed beside the lamp enables one to see 

 the time by night very plainly. 



AN "ALARUM" LAMP. 



The apparatus represented below (fig. 888) is an ordinary "alarum" lamp. 

 It is surmounted by a petroleum lamp, which carries a burner that remains 

 lighted all night, and which serves as a night-light. The " alarum " carries 



Fig. 888. An " alarum " lamp. 



an index, represented by the dotted lines in the illustration, and the hands 

 are fixed (with the index) to the hour you wish to rise in the morning. 

 The index is fitted with an arrangement which lets loose a vertical bar 

 represented on the right of the figure. This bar is held by a spring, and 

 carries a toothed rack which acts upon and raises the wick. At the proper 

 time the bar is loosed, and the lamp-wick is raised, diffusing a strong and 

 sudden light through the apartment. This illumination, in concert with 

 an alarum-bell, generally succeeds in awaking the heaviest sleeper. 



