tn the Counties of New-Haven and Litchfield. 217 
excavation, exposes to view a ledge of gneiss in the upper 
part of the mine ; it was inaccessible, but fronr its appear- 
ance and from the fragments which had fallen below, no 
doubt could be entertained that it was gneiss, —— y as 
this rock constitutes all the neighboring country. ~ 
~The clay which forms: ~~ immediate enveloping matter 
ids ; good colours for painting might be selected from them. 
Some parts of the clay appear very saponaceous, and the 
workmen assured me that a true fuller’s earth, answering all 
ae purposes of that useful. mineral, had been obtained 
A fuller’s earth’ is a clay usually: soapy in its Fickle ty 
slidothens of grease and oily matters ; fine in its texture, so 
as to present no parts that shall be large and harsh enough 
to injure cloth or wool, mechanically, by rubbing ; it should 
to powder easily in water, so as to diffuse itself through 
that fluid, and easily mix with it and with the stuffs to which 
itis applied. The fuller’s earth of Hampshire, England, so 
th celebrated, is of a greenish yellow, tolerably firm, 
erumbles easily in water, receives a polish from the finger 
nail,and is very powerfully detergent. This is, after all, the 
ant criterion by which to distinguish fuller’s garth’; : 
ifi it removes grease with avidity, crumbles easily in wa- 
ter so as to diffuse itself readily,and yet is not so coarse as 
to wear the fibre, it is a fuller’s earth. The subject is of some } 
practical importance to this country ‘on account of its wool- 
len manufactur es, — although checked for the present, | 
must eventually rise and prevail. While wes are of seen 
extent it may be neti to use soap, but i lar 
tablishments, fuller’s earth from its cheapness { et % 
can be abundantly obtained) is very esira 
ith respect to the existence of fuller’s wos in the clay 
of the Kent iron bed it appears very probable, and some of 
the specimens appear very like the Hampshire earth, but 
bs icra ents alone can decide. 
This vast bed of clay, (for it occupies more or less the 
h of the pit) is without any reasonable doubt, in- 
terposed between ledges of gneiss, which — form its 
‘oof, and appear to form its pavement. 
