Tunnel of Mount Cenis,—Cordier. 101 
he second unpublished document in this volume is by Leblanc, the 
inventor of the process for preparing soda from sea salt. This docu- 
ment relates to the mode of action of nitrogenous substances employed 
as fertilizers. 
above the road which leads to Turin across Mount Cenis. The subter- 
ranean way is 1338 metres (4390 feet) above the level of the sea. It has 
above it 1610-73 metres of caleareous rock. By reason of this enormous 
superincumbent mass, it is not possible to open ventilating shafts. 
The road will be subterranean through its whole extent and have no 
communication with the free air except at its two extremities. The 
length of the tunnel will be 12250 metres (40,191 feet or a little more 
than 74 miles). 
As yet the work of iercing the tunnel has advanced very slowly: on 
the side of Dardeniitehe it has not advanced beyond 600 metres, and 
problem more difficult to be resolved arises from the necessity of 
renewing the air in the interior of the tunnel, on account of the resistance 
which the compressed air meets with in the ventilatin tubes.” é 
tubes are 20 centimetres (about 8 inches) in diameter. The friction which 
they exert increasing in proportion to the distance passed over will be 
Very great, perhaps not admitting of a solution. The question will be to 
give motion to machinery in the tunnel by means of air compressed in 
reservoirs with walls sufficiently stron as in 1858 in this 
Journalt as a motor suitable for working in long tunnels. 
Osrruary.— Cordier (Pierre, Louis, Antoine) died the 30 of March 
last at the age of 84 years. Born at Abbeville March 31st, 1777, in 
1793 he entered the school of public works and passed in 1795 into the 
Corps des Mines. He joined the expedition to Egypt as a member of the 
Scientific Commission. He there 
espec 
return to Europe having been shipwrecked upon the coast of Calabria he 
profited by the misfortune by studying the mineralogy and geology of 
* This Journal [2], xxv, p. 96. } Ibid. [2], xxvi, p, 98. 
