A Letter from Mr. J. Ritchie, the late African Traveller. 69 



MM. Carlini and Plana. The present tables, as their title 

 imports, are founded entirely on the theory of gravitation ; and 

 are a proud monument to the genius of our immortal Newton. 

 The equations depend wholly on mean motions, similar to the 

 tables of Clairaut : and, from the list of 50 comparisons at the 

 end, they appear to be deserving of the highest credit. 



We regret, however, to state that these tables are arranged 

 according to the centesimal division of the quadrant, and the 

 decimal division of the day: which renders it necessary to re- 

 duce the result to the sexagesimal notation, and to the civil 

 mode of reckoning time, belbre they can be of any use to the 

 public. We are much surprised that the French will per- 

 severe in arranging some of their best tables in this manner : 

 since it only entails double trouble on the computer. If any 

 decimal notation at all is required for the convenience of com- 

 puting the equations, it would be much better to divide the 

 degree into decimal and centesimal parts; and this would 

 prove rather a convenience than otherwise to the computers. 

 The degree would be the unity of comparison, and would gra- 

 dually lead to the abolition of the use of signs. But the pre- 

 sent arrangement has nothing in common with that which has 

 been so long established ; and is moreover continually leading 

 the computer into errors. At all events, if the French will 

 persevere in the use of the centesimal division, they ought to 

 adopt a new set of characters for expressing their degrees, mi- 

 nutes, and seconds; and not usurp those in general use, which 

 denote quantities totally different, and thus lead to endless 

 confusion. 



A LETTER FROM MR. J. RITCHIE, THE LATE AFRICAN TRAVELLER, 

 TO A FRIEND IN ENGLAND. 



My dear M., Tripoli in the West, Jan. 21, 1819. 



I have not forgotten my promise of writing to you before I 

 left Tripoli, whatever you may have thought from the length 

 of time that I have deferred its performance. I believe the 

 moment of my departure will be soon approaching ; and, al- 

 though I have remained at this place much longer than I ex- 

 pected, it is a delay which I cannot regret, as it has afforded 

 me an opportunity of acquiring some knowledge of the lan- 

 guage, and of making excursions in the neighbourhood which 

 nave given me a more just idea than I before had of what will 

 be wanting in the course of my journey. We have been able 

 also to collect a number of objects in natural history, which I 

 hope will prove interesting to our friends in England, and 

 convince people (Sir J. Banks in particular) that the obstacles 

 which they supposed to interfere with all researches of this 



nature 



