5 26 THE POPULAR SCIENCE MONTHLY. 



Thus we are on the wrong road when we look for too ingenious 

 means for developing the chest ; this result, precious above all, 

 can be obtained without any complicated appliances, without any 

 difficult process ; and if we had to formulate concise advice on this 

 subject we should say : 



When a young person has a narrow and flat chest, recommend 

 running if he be a boy, or skipping if a girl. 







CANADIAN ASBESTUS: ITS OCCURRENCE AND USES. 



By J. T. DONALD, M. A., 



PROFESSOR OF CHEMISTRY, MEDICAL FACULTY, BISHOP'S COLLEGE, MONTREAL. 



ASBESTUS is a singular mineral, whose characteristics are well 

 - indicated in the various names by which it is known. The 

 French Canadian miners call it pierre a colon i. e., cotton-stone. 

 The Germans speak of it as Steinflaclis, stone-flax ; and amianto, 

 the Italian name, indicates that which is undefiled, in allusion to 

 the fact that it may be cleansed by fire. Asbestus, the name by 

 which it is generally known, is a Greek word, signifying endless, 

 ceaseless, and points to its fire-resisting properties. 



Asbestus is, then, a mineral occurring in a fibrous form, the 

 fibers being so fine and flexible that they may be spun and woven 

 as cotton and flax are ; and, moreover, the fabric so obtained is 

 capable of resisting a very high temperature. Some varieties are 

 said to have resisted a temperature of 5,000 Fahr. It must be 

 noted, however, that although this mineral is infusible, except at 

 extremely high temperatures, its fibers lose their flexibility and 

 become brittle at a temperature only sufficiently high to deprive 

 it of the water which forms a part of its composition. 



By the mineralogist the term asbestus was originally applied to 

 a finely fibrous form of hornblende ; but, as Dana adds, much that 

 is so called is a fibrous form of serpentine. Most if not all the as- 

 bestus of commerce is fibrous serpentine. A recent analysis made 

 in the writer's laboratory showed the following composition : 



Silica 39-05 per cent. 



Magnesia 40-07 " 



Alumina 3-G9 " 



Oxide of iron 241 " 



Water 1448 " 



Undetermined -30 " 



100-00 



This mineral has been known from very early times, but it is 

 only within recent years that it has found any extensive applica- 

 tion in the various industrial arts. In ancient Greece the bodies 



