LIFE OF THE AUTHOR. XXXVll 



answer (although I had never seen him during my 

 stay at Edinburgh) and informed me that I had 

 only mistaken the radical mean place of the as- 

 cending node by a quarter of a degree ; and that, 

 if I would send the drawing of my Rotula to him, 

 he would examine it, and endeavour to procure 

 me a subscription to defray the charges of engrav- 

 ing it on copper-plates, if I chose to publish it. 

 I then made a new and correct drawing of it, and 

 sent it to him, who soon got me a very handsome 

 subscription by setting the example himself, and 

 sending subscription-papers to others. 



I then returned to Edinburgh, and had the Ro- 

 tula-plates engraved there by Mr. Cooper.* It 

 has gone through several impressions, and always 

 sold very well till the year 1752, when the style 

 was changed, which rendered it quite useless. 

 Mr. Mac Laurin received me with the greatest 

 civility when I first went to see him at Edinburgh. 

 He then became an exceedingly good friend to me, 

 and continued so till his death. 



One day I requested him to shew me his orrery, 

 which he immediately did. I was greatly delight- 

 ed with the motions of the earth and moon in it, 

 and would gladly have seen the wheel- work, which 

 was concealed in a brass box, and the box and 

 planets above it were surrounded by an armillary 

 sphere. But he told me, that he never had open- 

 ed it; and I could easily perceive that it could 



* Cooper was master to the justly celebrated Mr. Robert Strange, 

 who was at that time his apprentice. 



