154 liemarko on Dr. Eiifieiil^s Institutes 



D 's mean anomaly;" and over the Vlb, " Arg. IV — 0'* 

 mean anomaly," Both these argutiients are wrong. Those 

 who may have the curiosity to look into Mason's edition of 

 Mayer's Lunar Tables, from which Ewing's were abridged, 

 will see at a glance how these erroneous captions originat- 

 ed. They are in fact the 3d and 5th arguments of Mayer's 

 tables; but Mayer's 3d table is omitted, and his 10th is^ 

 made Ewing's 5th. The captions were inadvertently cop- 

 ied, although they belonged, in consequence of these omis- 

 sions, to the wrong tables. In the last edition, the caption 

 of the third table is altered to make it agree with the gene- 

 ral directions for finding the arguments of Latitude given in 

 Prob. 8th ; but that of the 5tl) still remains erroneous, as 

 well as the general rule under Prob. 8th. It should be, 

 " subtract the moon's mean anomaly from the second argu- 

 ment," &;c. ; and the caption of table 5th should be, " Arg. 

 II. — D 's mean anomaly." 



The principal part of the corrections and alterations made 

 by the editor of the last edition have our entire approbation. 

 Particularly in regard to two highly important propositionSj 

 the one relating to the law of refraction, in the Optics, and 

 that on the sun's parallax, in the Astronomy, he has probably 

 done the best that the elementary character of the work 

 admitted. There are a few instances, however, of altera- 

 tions, the propriety of which appears very questionable, 

 and which justice to tiie labours of former editors requires 

 us briefly to notice. 



Thus in the first proposition, " Matter 'may be, and mere 

 extension is infinitely divisible," the clause in italics is pe- 

 culiar lo the last edition. We recollect having seen in 

 Hutton's Dictionary an attempt to establish a distinction be- 

 tween " actual" and " potential divisibility ;" but we could 

 not understand it ; nor are M'e any more fortunate in regard 

 to the language just quoted. If the terra '^ divisibility" it- 

 self means nothing more than the possibility of being di- 

 vided, to say that matter ma7/6e infinitely divisible is a sole- 

 cism. The distinction between the divisibility of matter 

 and that of extension seems to depend on the definition of 

 the term. If by " divisibility" be meant merely the pos- 

 sibility of being ideally divided by mathematical planes 

 without any separation of parts, then the property is one 

 which belongs to matter and to extension in precisely the 



