300 SCIENCE IN SHORT CHAPTERS. 



limestone regions, which have been disturbed by volcanic 

 action of the Miocene period. The travertines of Italy are 

 found in the neighborhood of extinct volcanoes. 



The classic associations of this material, its remarkable 

 stability, and the faculty with which it may be worked, 

 render it worthy of more attention than it has yet received 

 from British builders. 



THE ACTION OF FROST IN WATER-PIPES AND 

 ON BUILDING MATERIALS. 



POPULAR science has penetrated too deeply now to render 

 necessary any refutation of the old popular fallacy which 

 attributed the bursting of water-pipes to the thaw follow- 

 ing a frost; everybody now understands that the thaw 

 merely renders the work of the previous freezing so disas- 

 trously evident. Nevertheless, the general subject of the 

 action of freezing Avater upon our dwellings is not so fully 

 understood by all concerned as it should be. Builders and 

 house-owners should understand it thoroughly, as most of 

 the domestic miseries resulting from severe winters may be 

 greatly mitigated, if not entirely prevented, by scientific 

 adaptation in the course of building construction. Now- 

 a-days tenants know something about this and select ac- 

 cordingly. Thus the market value of a building may be 

 increased by such adaptation. 



Solids, liquids, and gases expand as they are heated. 

 This great general law is, however, subject to a few excep- 

 tions, the most remarkable of which is that presented by 

 water. Let us suppose a simple experiment. Imagine a 

 thermometer tube with its bulb and stem so filled with 

 water that when the water is heated nearly to its boiling 

 point it will rise to nearly the top of the long stein. Now 

 let us cool it. As the cooling proceeds the water will de- 

 scend, and this descending will continue until it attains 

 the temperature marked on our ordinary thermometer as 

 39, or more strictly 39^; then a strange inversion occurs. 



