4*7

THRAUSTOMICTHES.

It makes no effervescence with Aqua Fortis.

In the fire it acquires a dusky brownish red, with no great hardness.

It is dug in Northamptonshire, and many other parts of England, and is sometimesu fed in mixture in brick-making. At Peterborough it is us’d, mix’d with a brown stiffGay f or making the bellfounders moulds.

8. ’ThrauflomiBhes flavo-fusca.

XeMomJh brown Thrauftomi&hes.

This is a common brick Earth about London, and in many other parts of thekingdom; while in the stratum, it is commonly moist, but not tough or viscid;tt cuts easily, but falls into rude rough pieces, and leaves -an irregular surface behindthe spade; when dry, it is of a pale yellowish brown, of a loose crumbly texture,a nd not so heavy as most of the other Loams:, it is of a rough and somewhatdusty surface, adheres not at all .to-the tongue, breaks easily between the singers, anddoes not at all stain the hands; it melts freely in the mouth, but is coarse and harsh ina great degree betweeri the teeth ; thrown into water, it makes a flight ebullition andhissing, and immediately falls into a loose powder.

Examined by the Microscope, it appears of a very loose texture, and compos’d of amixture of a white and yellQW Sand, with a small quantity of a fine brown Clay.

It makes a considerable effervescence with Aqua Fortis.

It burns to a fine high red, but without much hardness.

It is dug in many parts of the Kingdom, and when work’d alone, and properly burnt,makes the fine red bricks us’d in the ornamenting buildings; but about London, most°f it is mix’d with ashes and tougher Clays, and made into the common pale red bricks.

SERIES!

.• C.L ASS. h 1 O. RD E R I. - G.ENUS I!

GLISCHROMICTHES.

. L’he tougher and 7nore viscid Loams.

• i. GlischromiBhes albido cinerea.

Greyish. white. GlischromiBhes .

T HIS is of a dense, compact and less crumbly texture than most of the Loams;

while in the Earth it is moist, soft, and in some degree viscid and tenacious, it cutsVer y easily and evenly through with the spade, and leaves a smooth and in some degreeglossy surface behind it; when dry, it is of a pale blueifh or afh-colour’d grey, veryheavy,, of an even and compact texture, and spangled with a multitude of small^Uttering particles; it is of an even and smooth surface, adheres pretty firmly to thet°ngue r is tolerably soft and smooth to the touch, cannot be broken between the sin-gers, uor does at all stain the hands ; it melts but very slowly in the mouth, and is! e fs coarse and gritty than most of these Earths between the teeth; thrown into water,Jt makes a flight ebullition and hissing, and after a little time breaks into small lumps,a nd from them soon after falls into a loose powder.

Examin’d by the Microscope, it appears of a fine and somewhat compact texture,is compos’d of a fine white sand, held together by a pale blueifh clay, and fpan-Ekd with a multitude of small plated fragments of Selenitæ.

It raises a great effervescence with Aqua Fortis.

. It burns to a great hardness, and a handsome, red, but is very apt to burst inme fire.

It is dug in many counties in England, and makes a very valuable brick, but re-hmres so much working that it is seldom us’d alone ; there is a stratum of it in thegieat clay pic behind St. George’s Hospital, at about eleven feet deep, and they mix itere with the other brick clays.

2 . Gliscromidikes