SCIENTIFIC SUMMARY. 
253 
Genova says : — “ The piercing of one of the most important tunnels of the 
railroad of Eastern Liguria has just been completed ; we mean the Ruta, 
which connects Camoglia with San Margherita by a passage of 3,050 yards. 
The termination of this important work does away with the most serious 
difficulty to the opening of the branch line from Genoa to Chiavari.” 
The Minerals of Lake Superior. — In the Canadian Journal there is a note 
by Professor Chapman, announcing the discovery of native lead near Dog Lake. 
It occurs in the form of a small string in white semi-opaque quartz. The quartz 
contains no other substances, with the exception of a small quantity of specular 
iron ore ; the absence of gold is noteworthy, as in the European localities 
where native lead has been found it is generally accompanied with gold. 
He also records the occurrence of Galena, Marcasite, Molybdenite, Barytine 
or Heavy Spar, Fluor Spar, and Anthracite, in the vicinity of Lake Superior. 
j Romeine. — At a late meeting of the French Academy, M. Bertrand de 
Lorn presented a note on the above subject. The mineral traverses vertically 
the mass of the manganese of Saint-Marcel. M. de Lorn has found that 
romeine may be obtained in the form of beautiful microscopic crystals by 
submitting the substance containing it to sublimation. 
New Source of Jasper. — Hitherto the supplies of this handsome mineral 
have been obtained, and then even in limited quantity, from Russia and 
Siberia. Now, however, it is obtained abundantly at St. Gervais, in Savoy, 
where the quartz from which it is derived has a surface of at least 24,000 square 
yards, and a depth of about 22 yards. It is a variety of quartz, which is 
characterized by being opaque, however thin the plates into which it may be 
cut, and is of various colours — red, brown, green, &c. ; that at present used 
for jewellery being green, with red spots. It resists for indefinite periods the 
action of the weather, and is an excellent material for ornamentation, whether 
as stands for small objects, &c., or as panels, columns, &c., to be used by the 
architect. Some of what is found at Saint Gervais bears close resemblance 
to the beautiful species termed rouge antique ; it is of a fine red, and without 
veins. — Vide the Scientific Review, March. 
New Artesian Well in Paris. — A third artesian well is now being added 
to the two which Paris has already. Already the perforation has reached 
the depth of eighty-two metres, being twenty metres below the sea-level. 
Before reaching this point, considerable difficulties had to be overcome in 
the shape of intermediate sheets of water, which form a series of subter- 
ranean lakes. The first of these was kept in its bed by means of a strong iron 
tube driven perpendicularly through it ; that which followed received wooden 
palings, and the subsequent stratum being clay, the masonry was continued 
without difficulty to about five metres above sea-level. But at this point a 
layer of agglomerations was reached, which let a great deal of water escape. 
It thus became necessary to have again recourse to pumps : those employed 
were in the aggregate of 20 horse-power. Owing to the bad nature of this 
stratum, it was resolved to protect the perforation by a revetement of extra- 
ordinary thickness ; and in order that the well might preserve its diameter 
of two metres notwithstanding, the upper part has had to be widened in 
proportion, so as to give it the enormous width of four metres at the top. 
After this labour the work of perforation was continued through a stratum of 
pyrolithic limestone. At the depth corresponding to the level of the sea, 
