LITHOLOGY. 51 
During tliis same period Kentish Rag (a hard grey limestone) 
was brouglit from the neiglibom-liood of Maidstone_, and em- 
played for ruder purposes ; tlie basement of Henry VII. Chapel 
is of this material; about this time (A.D. 1600J Portland be- 
came the general stone used for superior buildings in London, 
and the South of England. Inigo Jones having been deputed 
by James I. to sui'vey the crown' lands at Portland led to its 
introduction ; at first all that was obtained came from thence (the 
locality of these lands being on the North East of the Island)^ 
but as the demand increased large quantities were brought from 
the West and South East Cliffs, without the slightest regard to 
dm-ability, quality, or any other consideration of fitness than that 
of meeting with an immediate sale. 
Portland Stone of the most dm'able quality is comparatively 
heavy, of an uniform colour, rather dark, (owing to the quantity 
of cement,) of a crystalline texture, regularly dispersed through- 
out the pores, and hence it will resist a greater force to crush it, 
or to disintegrate the particles. The follomng comparison will 
show the relative peculiarities of good and bad Portland stone, 
considering the specimens, when examined, subject in every 
respect to the same conditions, such as being equally wet or 
dry, &c. 
Good. 
Preponderance of weight 
Dark coloured 
Uniform colom* 
Compact and Crystalline 
Hard to crush 
Bad. 
Deficiency of weight 
Light coloured 
Party coloured 
Open and powdery 
Priable 
Glass veins as they are technically termed are no defect, they 
only cause the surface to wear irregularly, and when all other 
parts became colored with lichens or dirt, remain completely 
white. According to the report of Professors Daniel and Wheat 
stone, appended to the report on the selection of stone for 
