48 > F E A R T H S. 



in water. It effcrvefces with Aquafortis. In the fire it acquires a 

 fine deep-red, with very little additional hardnefs. 



It is inferior in quality to the light ochres, but is greatly ufed 

 in painting. It is the yellow ochre of the fhops. 



A friable, clayey yellow ochre (q) is in a fear by the brook at 

 Birch-Crook, near Sbitlington~ha.il, in Tynedale, in a thick ftratum, 

 above another of black clay. Moift, it is of a dull dufky yellow, 

 moderately heavy, and fhattery on being cut through with a 

 fpade ; foft in handling, and tenaceous ; melts in the mouth 

 with a little grittinefs ; raifes a fmall ebullition in water, with a 

 hifling noife, mouldering or breaking flowly to a powder. De- 

 purated, and worked into a pafte, it is of a clear ftrong yellow. 

 It does not effervefce with Aquafortis. In the lire it acquires a 

 pale red, and a confiderable hardnefs. It is ufed in painting. 



A light, friable, faffron-coloured ochre (r) is frequent about 

 the adits of many of our coal-mines, and chalybeat fprings. 

 By the two fprings at Dibden, near Rothbury> it is in great abun- 

 dance ; half a foot, or a foot thick in fome places, by the ditch- 

 fides, made to carry off the water, We have it alfo plentifully 

 on the flrand of the rivulet by the coal-work at Simonburn, and in 

 a fmall rill at J3runton-hall, near Cbollerford-bridge, coating the 

 ftones, and other things in its way. It is of a light dufty fur- 

 face, and extremely lax and fliattery, foft to the touch, flains 

 the hands, and melts freely in the mouth. In water it raifes an 

 ebullition, with a hifling noife, but does not break eafily to a 

 powder. It does not effervefce with Aqua fortis. In the fire it 

 acquires a fair red. It is found in different degrees of purity. 



(q) Ochra argillacea fordide flavefcens. Hill. Hift. FofT. p. 55. No. 9. 

 (r) Ochra leviffima flava friabilis. Hill. Hift. Foil", p. 52. No 3. 



A light 



