t4 TRANSACTIONS OF THE [ DEC. 1%, 
The trap affords paving-stone of great durability and is available 
for those parts of the city bordering on the docks, where heavy 
slow-moving vehicles are used, but it would add very much to 
. the value of this pavementif the blocks were made narrower and 
the roadbed was more carefully prepared. Granite of excellent 
quality can be brought to the city from the banks of the Hudson 
about West Point, at a cost as low as such material can be ob- 
tained in any city in the world. Bluestone can be furnished at 
a still lower price. It makes the best flagging and curbing of 
any material known, and would supply paving-stones fully equal 
to those made of the psammite of Condroz or the Fontainebleau 
sandstone. 
For asphalt pavements, all the requisites can be obtained here 
of excellent quality and at a relatively low price. 
Many years ago a series of experiments made by Mr. A. C. 
Campbell, at the School of Mines, showed that the Trinidad as- 
phalt, which can be brought here cheaply, could be mingled 
with sand and other substances, so as to produce a mastic equal 
in strength and durability to that formed from the Swiss or the 
Sicilian rock; and lately more thorough and extended investiga- 
tions made by Mr. H. C. Bowen, have demonstrated that with 
proper treatment better results can be attained from artificial 
mastics, made from these materials, than from any natural as- 
phalt rock known. But the question of the possibility of making 
an excellent pavement from Trinidad asphalt has gone far be- 
yond laboratory experiments; for this is already done on a large 
scale and with great success by at least one asphalt paving 
company, the Barber, in several American cities. 
The paper was illustrated with specimens of asphalt, etc., from 
various localities. 
Remarks were made upon the subject treated of in the paper, 
by Messrs. CHITTENDEN, CoLLINGwoop, HoLBrook, MARTIN, 
and 'TROWBRIDGE. 
Mr. WiLirAm Coopsr exhibited a series of polished slabs of 
the beautiful aragonite breccia (called ‘‘ mosaic agate”) from the 
volcano of Zempoaltepetl, in Southern Mexico, near the Central 
American line. He described the locality, which he had re- 
cently visited, though heretofore very remote and inaccessible, 
and gave some account of the mode of occurrence of this material, 
which it is now proposed to introduce for ornamental purposes. 
The specimens were greatly admired; and remarks thereon 
were made by the President. 
