98 PHILOSOPHICAL TRANSACTIONS. [aNNO 1684. 



Scotia Illustrata, sive Prodromus Histories Naturalis, iic, Authore Roberto Sib- 

 haldo, M.D. Equite Aurato, Medico et Geographo Regio, et Regii Medi- 

 corum Collegii apud Edinburgum Socio. Edinburgi, in foL ]684. N° l65, 

 p. 795. 



This author, being the king's geographer for Scotland, undertook to publish 

 an atlas of that country, in a set of maps; preparatory to which, he printed this 

 introductory account of that country, containing the geographical and topogra- 

 phical descriptions of several parts ; including the curiosities and peculiarities, 

 the natural history, mines, soil, productions, people, animals, vegetables, &c. 



Extract of a Letter from Dr. John JVallis to the Editor Dr. Robert Plot ; con- 

 cerning two very large Stone Chimney-pieces, with a peculiar Sort of Arch- 

 work thereon. N° 166, p. 800. 



At Edgecot, in Northamptonshire, at the house of Tobias Chancey, Esq. I 

 have seen in an old kitchen, now disused, two very large chimneys of stone- 

 work, with a peculiar arch-work in the front, whereby, without the advantage 

 of a discharger of timber, as is usual, to defend the arch-work from being over 

 burdened, an arch of massy stone in each of them sustains itself, at a great 

 length, though almost on a flat, being very little raised in the middle. As this 

 seemed to me somewhat extraordinary, I caused a draft of one of them to be 

 designed, as in fig. 2, pi. 3. In which the lower arch-work, very little raised 

 from a flat, is made of large stones, so locked into one another, as appears in 

 the figure, that there might be the less danger of any one dropping out, or 

 being forced down, to the destruction of the whole. Over this, after some wall- 

 ing interposed, there is another arch to defend the former, more raised from 

 the flat, made of lesser stones, and with straight joints, not locked as the 

 former. Over all which the walling was continued upwards, in an ordinary 

 manner, forming, with the back, two vast tunnels of stone, and between 

 them, over the middle of the chimney, a large window. The dimensions of 

 the parts are here subjoined, viz. 



AB the breadth between the jambs, from inside to inside, 18 feet; CD the 

 depth of the stones in the lower arch 22 inches, locked into one another with 

 a crooked joint, and the number of them as in the figure; DE the distance in 

 walling between the arches, 2 feet 7 inches; EF the depth of the stones for the 

 upper arch, 15 inches, with a straight joint ; GH the place of the two tunnels; 

 K a window between them. 



The other chimney facing it, on the opposite side of the same kitchen, was 



