100 Protection of Persons from Fire. 



ical processes, as well as the action of steam, upon considerable 

 masses of it, in strong vessels ; but the result has not corresponded 

 with the expense of the process. He deems it better, therefore, af- 

 ter washing the amianthus, to loosen the fibres by rubbing or beating 

 it with wooden mallets ; or, if it be in compact masses, with iron 

 hammers, and immersing it repeatedly, in order to separate the fila- 

 ments and render them supple. 



In spinning the prepared amianthus, the use of the distaff is found 

 to be inconvenient, in consequence of the ends of the short fibres 

 presenting themselves perpendicularly, and thus breaking the thread. 

 The best method is to place the wool between two cards or paste- 

 boards, with a weight upon the upper one, as is done in the case of 

 silk, and the spinning becomes immediately safe and easy. Oil is 

 to be excluded from the spinning of this mineral. The author's ex- 

 perience also induces him to reject entirely the combing and carding 

 of the material, and also the practice which Ciampini had recom- 

 mended more than a century ago, of introducing in the spinning one 

 thread of flax with three or four of the amianthus. It is highly inex- 

 pedient thus to mingle a combustible substance with the texture of 

 that which is meant to resist the fire. 



It is not to be understood that a cloth of this substance is abso- 

 lutely incombustible. Like all other mineral bodies, it will melt at a 

 very high temperature, and either vitrify or undergo decomposition. 

 Being composed in part of carbonates of lime and magnesia, their 

 saline ingredients are decomposed at a temperature somewhat below 

 ignition. Hence in a furnace or before the blow-pipe, or in the fo- 

 cus of a burning mirror, it undergoes a change of composition and a 

 diminution of weight ; but as a large fragment or cord of it is less 

 easily affected by fire than a small one, M. Aldini finds that the best 

 cloth is obtained by making the chain of a double thread, and the 

 warp single. If the threads be too coarse the texture is not so good, 

 and the cloth is too heavy. Portions of amianthus, which, on ac- 

 count either of the shortness of its fibres, or the impossibility of sep- 

 arating them completely from each other, will not answer for spin- 

 ning, may be converted into pasteboard. Sometimes this refuse is 

 mingled with a portion of good material, and made into paper. 

 Pasteboard of this materia], may in certain cases be substituted for 

 the cloth, which is always more costly. 



Amianthus destined for cards or pasteboard, must first be washed 

 and prepared, as if for spinning, except that the filaments need not 

 be separated. It is then to be pounded until it acquires a pasty con- 



