10 FIRESIDE SCIENCE. 



country which are lighted by the carburetted hydro- 

 gen gas which flows spontaneously from the earth ; 

 and there is good reason for believing that in these 

 localities water sufficiently warm for heating the 

 dwellings might be readily obtained by boring at 

 no great depth. It is quite reasonable to suppose 

 that there are localities in this and other countries 

 where it is possible to obtain from water and gas 

 springs sufficient material to light and warm build- 

 ings, and also sufficient mechanical power to work 

 machinery effectively. The surprising capabilities 

 of mother earth are as yet but imperfectly under- 

 stood, but in process of time, as our needs increase 

 and more knowledge is obtained of hidden resources, 

 we shall be able to avail ourselves of many salutary 

 agents of which we have not the slightest concep- 

 tion at present. 



No class of springs have awakened greater 

 interest, or provoked more discussion, than what 

 are known as intermitting springs. Such, springs 

 are active or inactive for longer or shorter periods 

 of time, some of them having" an intermission in the 

 flow, of several minutes' or hours' duration, while 

 others stop flowing altogether for days. The spring 

 at Poterbrunnen', in Westphalia, ceases for six hours 

 and then flows again for sjx hours, and the volume 

 of water is such that it turns three mills in its 

 course. Another spring, in the Jura Mountains, 



