62 THE EXCAVATIONS 



a specimen of the mortar from the fragment of a Roman 

 wall still to be seen in Manchester, was analysed in 1828 

 by no less an authority than Dr. Dalton, who found that 

 it contained 15 to 20 per cent, of carbonate of lime, some 

 clay and iron, and about 80 per cent, of sand."^ 



A comparison of specimens of mortar from Manchester 

 and Melandra is of special interest, for this reason : It is 

 more than probable that the Roman soldiers who built 

 Mancunium obtained the lime for their mortar from the 

 well-known Ardwick beds."* The existence of limestone 

 close at hand may account for the better quality of the 

 Manchester mortar. Melandra, on the other hand, lay 

 on the boulder clay, in the midst of the gritstone country, 

 and its builders could not (I think) have obtained lime- 

 stone nearer than at Ardwick or at Castleton, i.e., about 

 twelve or fourteen miles away. In the excavation of the 

 wall last year, especially on the east side, many pieces of 

 limestone were thrown out. I brought away a number 

 of these for Professor Boyd Dawkins to examine, and he 

 writes : " The limestones are hard masses of burnt lime- 

 stone^^ left when the lime was used for mortar. They 

 are crinoidal limestones, like those of Castleton, and other 

 places in Derbyshire." We thus obtain an interesting 

 glimpse into the past. We see the Roman carts,'^^ loaded 



73. Baines. Hist. Manch., vol. ii., p. 152. 



74. Rceder actually found in the limestone at Mancunium the Spirorbis 

 which is characteristic of the Ardwick beds. (Itom. Man., p. 79, seq.). 

 See also Mr. Pettigrew's analysis (p. 83) which, however, is perhaps not 

 so conclusive. 



75. Vitruvius has a separate chapter on the burning and slaking of 

 lime. His explanation of the binding effect of lime is interesting. 

 (De Arch., ii., 5.) 



76. May we not actually hear the creaking of the axles? 



montesque per altos 

 Contenta cervice trahunt stridentia plaustra. 



Verg. Georg. iii. 536. 

 Nee plaustris cessant vectare genientibus ornos. 



Verg. Aen. xi. 138. 



