364 Claim to the Invention of 



serviceable and alluring to youth, upwards of two hundred and 

 thirty beautiful wood-cuts are added, which, as being unexplained, 

 are sought after in the Latin, and provoke curiosity, as well as 

 elucidate. Such a plan has, I am happy to say, obtained the 

 favourable approbation of the first scholars of the age ; and our 

 Pastorals of Virgil have now passed through a third edition, and 

 seem likely to be adopted by school-masters in general*. 



LXIII. Claim to the Invention of a new Method of determining 

 the Latitude. By Mr. Edward Riddle. 



To Mr. Tilloch. 



Sir, — vJn the appearance of the last part of the Transactions 

 of the Royal Society of Edinburgh, I observed a communication 

 from General Brisbane, respecting a method of determining the 

 time, (which he of course conceived was either not generally or 

 not sufficiently known,) accompanied by a promise to transmit to 

 the Society an account of a method of determining the latitude 

 hy observations made near noon. The method of determining 

 the time which he detailed in that memoir, was exactly the same 

 as one which I had practised for a considerable period; and I 

 thought it, therefore, probable that his promised method of de- 

 termining the latitude might also be similar to that which I was 

 daily in the habit of practising. 



That a fair opportunity might be afforded of comparing our 

 methods, I immediately addressed a letter' to you on the subject, 

 containing a detailed account both of the principles of my method, 

 and of the manner in which the observations and calculations were 

 made ; and I added an example, with the calculations at length. 

 The observations for the example were taken, and the calculations 

 completed in the form in which they were sent to you, in the year 

 IS 17. My letter, I find, is dated'October 21, 1818, and it 'was 

 printed in the Philosophical Magazine for December the same 

 year. 



General Brisbane's method is now before the public. It forms 

 Art. XIV. Vol. IX. Part I. of the Edinburgh Phil. Trans., just 

 published; and it appears to have been read November 20, 1820. 

 The oljservations which are given as examples were made in 

 February 1820, more than a year after my letter on the subject 

 had been published in the Philosophical Magazine ; and more 



* We annex a Plate, to show the nature and value of the wood-cuts in 

 " Thornton s Paxtnrah of firgil, in which all the proper facilities are given, 

 enabling youth to acquire the Latin languajje in the shortest period of time, 

 with the utmost delight to the scholar, and case to the master. " — Editor. 



than 



