420 THE YARD, PENDULUM, AND METRE. 



the p7i7iciple of the meamre''')^ and it may therefore be 

 reasonably presumed that it will be brought forward 

 again in the next session, in tlie same or a modified 

 form. As the discussion it received in the House 

 seemed to be in no respect commensurate with the im- 

 mense importance and sweeping nature of the change 

 proposed, and with the exception of one or two rather 

 cursory notices in The Tivies^ excited a marvellously 

 small amount of public interest pending its progress ; it 

 will not be amiss if, being called upon by the committee 

 of the Leeds Astronomical Society for an exposition of 

 some point of general interest in the form of a Lecture 

 or Essay, to be read at one of their Evening Meetings, 

 I select this for its subject ; and endeavour to place be- 

 fore you the several conditions which any standard or 

 typical unit of length which shall be assumed as the 

 basis of a system of measures and weights intended to 

 be national, and which may justly claim to be universal, 

 ought to fulfil ; and to compare with these conditions, 

 in order to see how far they are fulfilled in fact, both 

 our actual standard, the French metre now in use, and 

 the length of the pendulum, which has been more than 

 once proposed as a natural unit of length. And this I 

 will endeavour to do in as elementary and familiar a 

 way as shall be consistent with perfect correctness. 

 Those of the present audience who are not already 

 familiar with the subject will thus be better enabled to 

 form an opinion as to the desirableness of the change 

 actually proposed, or of any legislative change in our 

 existing standard, and in our system of measures, 



