448 Scientific Proceedings, Royal Dublin Society. 



Cross, London, whicli had an ordinary pin- wheel escapement with 

 a remontoire train, I have so arranged the frame of this clock that 

 I can in a few minutes replace the gravity by such a pin-wheel 

 escapement. 



Sir E. Beckett justly observes that crucial experiments on the 

 rate of a clock can only be conducted when the clock is erected in 

 its own permanent position. 



I have therefore made arrangements to enable this clock, when 

 erected at Farmley, on the far side of Phoenix Park, to automati- 

 cally report its rate daily to me in Rathmines, and hope by this 

 means to be able to form in some months a fair estimate of the 

 value of the different kinds of escapement. 



3rd. The remontoire fan usually applied to turret clocks, which 

 has always appeared to me a very cumbersome and awkward piece 

 of apparatus, I have replaced by a little fractional governor, simi- 

 lar to what I use for equatorial clocks. 



I find this to work in a most satisfactory manner, and the whole 

 apparatus is enclosed in a box two and a-half inches diameter, while 

 the fan necessary to effect the same purpose would be at least two 

 feet diameter. 



4th. I have replaced the usual ratchet, which makes such a 

 disagreeable noise every one-third or one-half minute, by a pecu- 

 liar silent click, which is perfectly effective and absolutely silent. 



In other respects the clock has no peculiar feature, except that 

 its general arrangement is somewhat novel, and considering that 

 it has to work two eleven feet exposed dials, and start the strik- 

 ing part, which rings a peal of bells, the largest of two tons weight, 

 the escapement action is probably lighter than any hitherto made. 



The pendulum is a two-second pendulum. All the small pinion 

 in clock train are lantern, the smallest being made on the principle 

 described by me on a former occasion with reference to Siderial 

 clocks. 



The " letting off " of the striking part is somewhat peculiar. 

 The letting off cams are set up and placed in position by a slow 

 moving shaft, but the final letting off is effected by a cam on a 

 quick moving shaft, something after the manner of the Westmin- 

 ster clock. 



