THE ROYAL DUBLIN SOCIETY 49 



quay, and the Ballast Office boat made an expedition 

 with the machine fixed to the rudder, the index being 

 set at the last degree of the circle 50 degrees. At the 

 end of a mile, the index had moved 16 degrees. The 

 machine was contrived so that the index went round 

 50 degrees while the ship moved a league. The com- 

 mittee tested going with and against the tide ; with 

 the tide, the boat sailed a mile, while the index moved 

 1 5 degrees ; against it, the index moved 1 8 degrees in 

 a mile, so that there were more revolutions of the wheel 

 in going against the tide, and fewer in going with it. 

 A further trial of the machine was made in July, when 

 the committee decided that, for want of trials at sea, 

 they could form no judgment of its use when the 

 weather was stormy. Telfier was advised to bring it to 

 the Admiralty in England, where proper experiments 

 could be made, and the Secretary was directed to draw 

 up a certificate of the success of the trial here, Telfier's 

 instrument appearing to answer better than the log-line. 

 It might be supposed that a Glasgow man could have 

 had similar trials on the Clyde ; and it must be taken 

 as a special tribute to the position now occupied by the 

 Dublin Society that a Scotchman was anxious to bring 

 out his invention under its auspices. 



The volume containing the minutes between the 

 1 oth of July 1746 and the 3rd of May 1750 is un- 

 fortunately not now forthcoming. 1 As it, probably, 

 contained a record of the negotiations which led up to 

 the granting of the charter, the story of that important 

 event in the history of the Society has necessarily to be 

 omitted here. (See p. 75.) 



The newspapers of the day have to be fallen back 

 on for supplying a few details as to the ordinary work 

 of the Society. The practice was once more adopted 



1 This volume has been missing for nearly a century. 



D 



