XIX. Experiments upon the different kinds of marle found in Staffordshire

1, Red and blue intermixed, in fmall friable lumps. '.:2, Red, in [mall friable lumps. 3. Grey, in large hard lumps. 4. Red, hard, compact.. . 5. Red, with grey fpots, m large hard lumps, fcarcely to be broken with a hammer. 6. Light grey, like a grit ftone. 7. Brown, friable, in large lumps. 8. Red, in large friable lumps. · 9· Brownilh white, very hard, like calcarious incrufiations. 10. Lead colour, friable, flaky. 11. Brown grey, very hard, in irregular lumps. 1 2 . Lead colour, in powder and in final! hard lumps. Read Feb. 4, 177 3·