ECONOMICAL MATERIALS. 
The grey trenton limestone forms a fine material for building. The new Catholic cathedral 
at Montreal is built of this variety of the trenton. It resembles granite, and being equally 
durable, and much more easily wrought, ought to be preferred when it can be procured. 
Substances for clarifying syrups, water, etc. Slate for roofing does not occur in the Second 
district; but a variety suitable for flagging may be obtained south of Essex, on the lake in 
Essex county. This rock is used in France for clarifying sugar, syrups, etc. It appears that 
it is the bituminous variety ; and that in order to be employed, it should be burnt and then 
pulverized, when it is ready for use. The bituminous slate, it will be recollected, occurs at 
numerous places ; and as it is useful for the purpose specified, may it not also be used for 
purifying rain water for cisterns ? The decomposing slates of Loraine and Rodman may open 
a new field of industry to some of the inhabitants in the manufacture of alum. 
Hydraulic lime. Limestone for hydraulic purposes is abundant in the calciferous sandrock. 
Some variety of opinion is expressed in relation to its qualities, which probably arises from 
the want of care in selecting the strata intended for burning. 
Fire-stones. Rocks which will sustain a high heat without melting, cracking or exfoliating, 
are termed fire-stones. Of these rocks we have three : the Potsdam sandstone, the Rensse- 
laerite and Steatite. The first borders the district on three sides almost continuously ; but 
from this extended mass it is necessary to select those strata which are free from feldspar. 
This kind is used commonly in the northern counties for the hearths of furnaces ; and when 
the composition is right, that is, when composed of siliceous grains and uncrystallized in the 
mass, it is one of the best of fire-stones. Rensselaerite may be employed as a lining for 
stoves, and for all the smaller purposes which may require a substitute for steatite. I placed 
a small slab of it in the midst of ignited anthracite, where it remained several hours with¬ 
out suffering any change except becoming whiter and harder. Steatite is also found in Fowler, 
but it is not abundant in the northern district. 
Sand for glass. The great abundance of the potsdam sandstone removes the necessity of 
employing sand, although this exists at several places. Wherever it is found, however, it is 
derived from the potsdam. The material, either in the rock or in a state of sand, is in the 
greatest abundance. 
Sand for sawing, polishing, and sand-paper. The same material, as stated above, may be 
employed for either of those specified purposes. The rock therefore is one of the greatest 
importance, as we see when we enumerate the specific objects for which it may be employed. 
Glazing materials. The tertiary clay of Lake Champlain forms one of the finest materials 
for glazing common earthen ware. To glaze the articles, it is only necessary to dip them 
into a solution or mixture of the clay with water, of about the consistence of cream. The 
color will depend upon the subsequent burning. It is easy to show why this material may 
be thus used : the alumina is mixed with a quantity of carbonate of lime, which operates as a 
flux to the aluminous part. Glazing of a finer kind is found in the feldspars of Chester in 
Warren county, and in Gouverneur in St. Lawrence county, and several towns in the vicinity. 
The porcelain clay of Johnsburgh probably contains colored strata which may be employed 
for some purposes in pottery, either in glazing or forming the body of the ware. 
