Polytechnic Association Proceedings. 631 



with a veiy short peduncle of a very beautiful white color and 

 slightly rosy; the skin was distended and elastic under the linger. 

 After speaking of the chemical analysis of the plant, M. Baudimont 

 estimates the number of cellules in the ball at more than fourteen and 

 a half billions; and since it was fourteen days in maturing, over a 

 million of cellules were formed every four hours, or twelve thou- 

 sand per second! The spores are a hundred times more numerous 

 than the cellules. Think of 1,200,000 spores being formed between 

 two strokes of a pendulum, without any disturbance of the myste- 

 rious equilibrium which reigns within! How prodigious the energy 

 which consummates this growth! 



THE HOOSIC TUNNEL. 



While European engineers are engaged in piercing Mount Cenis, 

 to make a railway connection between France and Italy, American 

 engineers are steadily, but rather slowly, penetrating a spur of the 

 Green mountains at Hoosic, in order to complete a railway commu- 

 nication between the valleys of the Hudson and Connecticut, and 

 making a more direct route from Troy to Boston. The work is 

 progressing more rapidly on the eastern end, where, by means of 

 a water-power on the Deerfield river, air is compressed and forced 

 through iron pipes more than four thousand feet, to a point where 

 it keeps in constant motion a number of drills, and, when it has 

 spent its power on the pistons, furnishes the workmen with fresh 

 air. The advance through the solid rock on the eastern face is at 

 the rate of ninety feet per week. It is estimated that the tunnel 

 will be completed within five years. Nearly $2,000,000 have been 

 spent on the work. The central ventilating shaft has been sunk to 

 the depth of four hundred and fifty feet. When it has reached 

 one thousand one hundred and thirty feet, work will be commenced 

 at that point, in both directions on the main tunnel. 



ENGRAVING BY ELECTRICrTT. 



Gaiffe's electrical engraving machine, lately much improved, is 

 in the Paris Exposition. Any number of plates may be engraved 

 at once; the tool cuts them as in the ordinaiy lathe, and the rest is 

 operated by means of a platinum point, which passes over the 

 design made with a varnish. The point, in passing the varnish, 

 breaks the connection of the electric current, and thus demagne- 

 tizes an electro-magnet behind each graver, and allows a spring to 

 press the graver against the plate on each machine. When the 

 point touches the unvarnished part of metallic plate, containing the 



