Protection of Persons from Fire. 101 



sistence ; then mixed with common size, and subjected to the usual 

 process for making pasteboard. These sheets have sufficient con- 

 sistence to admit of being smoothed without abrasion. It has been 

 manufactured under the author's direction at Milan, Florence, Bo- 

 logna, and other places in Italy, in sheets of about half a yard long 

 and a foot wide. 



Chap. III. — JYeiv method of enabling firemen to preserve them- 

 selves from- the violence of fame. 



The author adverts to the power of the human body of sustaining, 

 by well known artificial expedients, extremes of temperature from 

 that at which mercury congeals, to that of the burning valley of the 

 Niger, and even, as in the case of Blagden, Fordyce and others, to 

 a heated air, exceeding in temperature that of boiling water. But all 

 these are vastly below the heat of flame. The only means of sup- 

 porting, even for a short period, such burning and destructive heat, is 

 a defence similar to that which the author proposes — the interposi- 

 tion between the exposed parts of the body and the burning source, 

 a substance which is at once a slow conductor, and incombustible. 



The finer the metallic gauze, that is, the smaller the wire, and the 

 more numerous the meshes, the better will it repel the flame. The 

 non-conducting substance must evidently be such as to resist violent 

 agitations of the air, and whirlwinds of flame, and of course it must 

 have strength and weight. Amianthus would be preferable to every 

 thing else, if it could be every where easily procured, and the prepa- 

 ration of its cloth were less expensive. 



To prove by a simple experiment the efficacy of metallic gauze, 

 the author takes two tubes of this wire tissue, the one enchased with- 

 in the other, but separated by a thin stratum of air. Its diameter is 

 such as to admit a finger clothed with amianthus. He then exposes 

 the finger fully to the flame of a lamp or candle for three or four 

 minutes with impunity. This is a much greater heat than that to 

 which firemen are generally exposed. 



In whatever way the defensive armors are arranged for the pro- 

 tection of firemen, the author lays down the following as rules of 

 practical importance. 



1. That the firemen avoid carefully all contact of their bodies with 

 substances that are rapid conductors of heat. 



2. That the armor be so prepared as to present the fewest pos- 

 sible openings. 



