426 THRAUSTOMICTHES.

5 . ThrauJlomiElhes sordide flavescens.

Deep , dusky yellow ThrauJlomiElhes.

This is a very coarse, harsh and friable Earth ; while in the stratum it is very moist,but not at all tenacious, easily cut thro' with the spade, but falling in irregular lumps,and leaving a rough surface behind it. When diy, it is of a very deep duskyyellow, of a loose incoherent texture, and very heavy; it is of a rough rugged surface,adheres but slightly to the tongue, is hard, harsh and rough to the touch, easily crum-bles to pieces between the fingers, and does not at all stain the hands ; it melts readilyin the mouth, but is remarkably coarse between the teeth ; thrown into water, it makesa very slight ebullition without any noise, and immediately falls into a loose powder.

Examin’d by the Microscope,' it appears to be a congeries of two very beautifulSands, a deep yellow, and a whitish one, with scarce Clay enough intermix’d to holdthem together.

It makes no effervescence with Aqua Fortis.

It burns to a deep orange colour'd red, with some little additional hardness.

It is dug in most parts of the kingdom, particularly in Dorsetshire, Northampton-shire, and about London, and us’d in brick making mixed with the tough fine Clays.

6. ThraufomiElhes durijfima , fusca.

Hard j brown ‘ThrauJlomiElhes.

This is a very hard but not at all tough or viscid Earth; while in the stratumit is very dry, and firm, not to be dug without pickaxes, and falls in great rudelumps; when dry it is of a dusky brown, of a very hard and firm consistence and greatweight, 'tis of a rough dusky surface, adheres pretty firmly to the tongue, is rough,dry, and harsh to the touch, is not to be broken between the fingers, and does not atall stain the hands; it breaks pretty freely in the mouth, and is very coarse and hard be-tween the teeth ; thrown into water, it makes a very slight ebullition without noise, anddoes not readily disunite or break in it.

Examin’d by the Microscope, it appears of a very firm texture, and compos’d of alarge white Sand embodied in a deep brown Clay.

It makes no effervescence with Aqua Fortis.

In burning it acquires a very deep red without any additional hardness.

It is dug in many parts of the kingdom, sometimes pure, but generally full of smallsea shells; in Staffordshire and Buckinghamstslre, they have it pure, and use it in brick-making; in Northamptonshire, they have it full of shells, and call it there PennyEarth, and use it on many occasions; when well beat together it dries into a very firmhard mass, and they make of it floors for barns, and other places; and cover the topsor ridges of walls, and thatch’d houses, and even the roofs of their ovens with it; it isof little less hardness when thoroughly dry than plaister of Paris, and bears the wea-ther extreamly well; we have vast quantities of this about Deptford and Woolwich,but I don’t find that we have ever brought it into any use there.

7. ThrauJlomiElhes levior 5 pallide fusca.

Light , pale brown ThrauJlomiElhes.

This is the loosest, lightest and most spungy of all the Loams; while in the stra-tum it is moist, and of a very lax rare texture, and very easily cut with the spade, butfalling irregularly from it; when dry, it is of a pale brown, with some flight cast osyellowisliness, of a spungy cavernous texture, and looking much like the Earths thathave been wash’d, and remarkably light for an Earth of this Class; it is of a rude, irre-gular and somewhat dusty surface, adheres not at all to the tongue, is dry, harsh andrough to the touch, easily crumbles to pieces between the fingers, and a little stains thehands; it melts very freely in the mouth, and is less coarse than many other Loamsbetween the teeth; thrown into water, it makes a considerable ebullition with somehissing, and almost immediately falls into a loose powder.

Examin’d by the Microscope, it appears of a very loose texture, and compos’d of afine pale yellow Sand, held together by a light brown Clay.

It