208 THE POPULAR SCIENCE MONTHLY. 



themselves more readily to the fanciful forms which manufac- 

 turers like to impose upon them. 



M. A. Petit, engineer, has described to us the processes of man- 

 ufacturing them thus : A paper pulp is taken composed of eighty- 

 five parts of wood pulp and fifteen parts of rag pulp, and is shaped 

 in molds to the desired form. The pneumatic or the centrifugal 

 process of molding is used, according to circumstances, and does 

 not differ essentially from those employed in porcelain factories. 

 The articles are dried in air and then desiccated in a current of 

 warm air ; after which they are placed in an iron cylinder of one 

 cubic metre capacity, which can be hermetically closed. A vacuum 

 is formed in the cylinder in order to withdraw the air from the 

 objects which are placed in it, and is maintained for four hours, 

 after which a liquid composed of petroleum essence, colophony, 

 linseed oil, and paraffin is admitted ; this liquid being heated to a 

 temperature of 75° C. before it is let into the cylinder. The ar- 

 ticles are kept immersed in it for a quarter of an hour, when they 

 are withdrawn and placed in a similar cylinder heated to 100° C, 

 for the purpose of expelling the petroleum and recovering the sol- 

 vent for use in other operations. The articles having been dried, 

 are exposed in a stove for five hours, at 75° C, in a current of elec- 

 trified air, or air containing a considerable quantity of ozone, for 

 the oxidation of the linseed oil which fills the pores of the pulp. 

 They are then plunged for an hour in a bath of linseed oil, castor 

 oil, and colophony ; exposed again in the stove to air and ozone, 

 after which they are completely impermeable, flexible, and proof 

 against acid. 



The adaptability of paper for the construction of canoes has 

 been proved by the strictest tests, and the canoes have been found 

 to be practicable boats ; but the manufacture of them has not been 

 as prosperous an industry as might have been anticipated. 



On the other hand, the application of paper in house-building 

 has been crowned with success. A builder's establishment founded 

 several years ago took for its device "Neither ivood nor iron" ; 

 and its houses, built almost exclusively of pressed paper, are 

 curious specimens of what may be done with that material. The 

 element of the construction is a panel, usually three metres by 

 one metre and sixty centimetres, and a tubular beam ten centi- 

 metres in thickness, and composed of two walls of pressed paper 

 four millimetres in thickness, fixed upon a frame, likewise of 

 paper. The pieces composing this frame are V or U shaped ; 

 and these devices, capable of giving extremely light joists or 

 beams, are not one of the least original of the conceptions of 

 the system. The elementary panels do not weigh more than 

 forty kilogrammes apiece ; they are easily handled, and they 

 fit at their edges so as to constitute the wall. The roof is com- 



