174 PHILOSOPHICAL TRANSACTIONS. [aNNO 1715. 



The 4th section shows how to find the representations of the reflexions 

 of figures made by polished planes. 



The 5th section contains a few propositions relating to the inverse method 

 of perspective ; or the manner of examining a picture already drawn; so as to 

 find out v/hat point the picture is to be seen from, or having that given, 

 to find what the figures are which are described on the picture. 



Our author has observed that there may be a very good expedient made use 

 of in painting of large rooms and churches, which is drawn from the nature of 

 those rays which produce the vanishing points. This not being mentioned 

 in the book itself, he thinks it not improper to take notice of it here : the ex- 

 pedient is this, having some way or other found the representation of one 

 point of a line that is wanted in the picture, to find the whole line, pass a 

 thread stretched through the place of the spectator's eye, in a direction parallel 

 to the direction the original line ought to be in, and the shadow of that 

 thread cast by a candle, so as to pass through the given point on the picture 

 will be the representation sought. The reason of this construction is, because 

 the rays of light that pass from the candle to the thread so stretched, make 

 the plane which generates the representation sought. (See Prop. 1.) And 

 there may be other expedients of the like nature gathered from the same 

 principle. 



//. Ducalus Leodiensis; or, The Topography of the ancient Toivn and Parish 

 of Leeds and Parts adjacent^ in the County of York, &c. By Ralph 

 Thoresby, Esq. F.R.S. London , fol. 1715. N° 344, p. 304. 



Though the author does not professedly treat of any place but the ancient 

 town and parish of Leeds, and the Regio Leodis, or adjoining territory called 

 Elmet ; yet not only the preface is more general, relating to the whole county, 

 but there are many passages in the book itself, where he takes occasion to insert 

 the pedigrees of such of the nobility and gentry, as have had any estates within 

 the prescribed limits, though the chief seat of the family be distant; as esteem- 

 ing all provinciales, who have but domicilium in provincia : to some of these 

 be has premised several descents from ancient deeds yet remaining in the re- 

 spective families : and to most of those that are inserted in the visitations in 

 the College at Arms, London, he has added the dates from original deeds, 

 registers, &c. and continued them to the present time. In the other parts, 

 relating to the topography and etymology of the names of places, &c. he has 

 been very particular, finding the name to be often a brief description of the 

 place; and hath been thereby enabled to discover the vestigia of some consider- 



