148 Miscellaneous Intelligence. © 
The expense of the bridges was as follows :— 
Masonry of the abutments, $c. . . . 4100 francs. 
lodges, stations, §c.. . 3800 
Forged iron, §c., for the gates. . . - 2800 
Iron wire and workmen . . . » . - 1940 
Wood-work required, workmen, Jc.  . 2250 
Lead, copper, tin, varnish, Jc. . . - 800 
Terraces for the parapets, foundation, §c. 160 
Various expenses . . . . . + ~ + 4500 
oe 
16,350 
Bib. Univ. xxiv. 297. 
2. Test for the action of Frost on Building Materials, by M. P. 
Brard.—MM. Lepeyre and Vicat knowing that I had been long 
occupied in the study of mineralogy as applicable to the arts, en- 
gaged me in an investigation of the means best adapted to distin- 
guish such stones, as, being otherwise fit for building materials, 
gave way to the action of frost. I found it impossible in this 
respect to ascertain any thing from their mineralogical characters, 
and was obliged to follow another course. During the winter of 
1819, I carefully examined with a lens the chalky limestone of 
the neighbourhood of Perigueux, and the sandstone of the 
coal basin of la Vezére, both equally liable to this action, I 
soon found that each scale of the limestone, and each grain of the 
sandstone was raised by the re-union of small needles of ice, which 
when they melted suffered the particles to fall and collect about 
the stone, and that where particles had fallen off in this way, a 
fresh succession was raised in the same manner, and ultimately se- 
parated from the mass. 
I was struck by the resemblance of. the ice in silky crystals to 
the saline efflorescences which appear between the plates of cer- 
tain shists and on the surface of old walls. I remembered the ef- 
fect of common salt on bad pottery, and on the saline rocks of 
the Tyrol, and conceived the idea of substituting the action ofa 
saline solution to that of common water. After various experi- 
ments, I gave the preference to sulphate of soda, its effects being 
the most constant and most comformable to the action of frost. 
The experiment that it may lead to satisfactory results should 
be conducted as follows. Suppose an excavation newly made 
into limestone or other rocks, and it be desired to ascertain the 
liability of the rock to disintegration by the action of frost. 
lst. A cube of two inches in the side is to be cut from each 
part to be tried; the various cubes numbered with thick China 
ink, and their original sites also marked. 
