64 Horology. 



Saturday, November 7th, 1868. 



The Fifty-third Meeting of the Society was held in the Vaughan 

 Library. Mr. Button and Mr. Watson were declared Honorary 

 Members. Gore, sen., was elected a member. 



The exhibitions were : — 



A fossil bone of an Elephant . . . . . . By Johnson. 



Some curious pieces of vitreous slag, from Mr. Penn's Engine Manu- 

 factory . . . . . . . . By the President. 



Hicks' minimimi mercurial Thermometer ; a very delicate Thermometer- 

 bulb . . . . . . By the Vice-President. 



The circulation in a Frog's foot, under the microscope . . By Mr. Leaf. 



Some Galena, from a silver mine, near Ems . . By Balfour. 



An Athenian obolus . . . . . . . . By Evans. 



The President communicated an account of the late Solar 

 Eclipse, in the proceedings of the Royal Society. 

 Howell then read a paper on 



HOROLOGY. 

 Of which the following is an abstract. 



After some remarks on the various time measures employed 

 from the earliest historical period to the present, the mechanism 

 of a clock was minutely described, and the various improvements 

 which it has undergone were explained. Among several others, 

 the dead and gravity escapements were specially described. 



As variations of temperature cause the length of the pendulum 

 to vary, and therefore, the period of its oscillation to alter, for 

 clocks where great accuracy is required, compensating pendulums 

 have been invented. Some of these were then mentioned and 

 described. 



A watch was next described, and the parts in which it differed 

 from a clock were more especially pointed out. The action of the 

 balance wheel which supplies the place of the pendulum was ex- 

 plained, and the three escapements principally used in the best 

 watches were noticed. 



The President made some remarks on Galileo's discovery of 

 the isochronism of the pendulum. The Vice-President mentioned 

 that the perfectly isochronous pendulum is that which oscillates in 

 a cycloidal curve. 



