BY HON. A. C. OREOORV, C-M.O., F.R.G.S. 



5 



the Town Hall and all its belongings a yard high above its foun- 

 dations, or lift one of the ocean steamers out of the river on to 

 the wharf. 



Electrical science has perhaps made the greatest advance of 

 late years. The telegraph, telephone, electric light, and motors 

 have sprung into practical existence in a comparatively short 

 period, and so extraordinary has been their progress that many 

 have been led to expect that electricity would supersede steam 

 power and gas hght ; but here science shows that as one pound of 

 carbon will absorb ten times the quantity of oxygan as a pound 

 of zinc, which is the most energetic direct source of electricity, 

 bo also does carbon develop ten times the energy which is given 

 by an equal weight of zinc ; and in actual practice it has been 

 found that the coal-burning steam engine is the most economical 

 source of electricity, vvhether used for pov/er or light. And 

 though the gas engine has been advantageously applied for this 

 purpose, it is only successful where limited space and intermittent 

 demand make it convenient to burn part of the coal at the gas 

 works, in making the gas which is to be burnt at the place Avli'cre 

 the power is used. Thus the gas engine is equally a coal-burning 

 motor with the ordinary steam engine. 



One of the more important results of the scientific investiga- 

 tion of heat, light, electricity, magnetism, and gravitation or motive 

 force is, that they are all convertible forms of one .and the same 

 condition of matter : a condition for which our language has not 

 yet supplied a separate specific term, and it has therefore been 

 provisionally designated " Energy." Energy, like sound, has not 

 a substantive existence, but is only the vibration of a substantive 

 mediufii through which its undulations or waves are transmitted. 



• 



The development of these facts has further led to the impor- 

 tant discovery, that though the nature of our terrestial atmosphere 

 is such that we cannot compute it to have a thickness of loo 

 n,iles — which is a mere film on the earth's surface — yet there must 

 be some clastic medium occupying the space beyond to the full 

 extent of the visible universe, for light, being only a vibration, 

 could not traverse an absolute vacuum, as there would be no 

 medium to vibrate and convey its undulations. 



Here we enter a vast field for speculative investigation with 

 datd which tend to the expectation that our present theories re- 

 garding the conditions of the celestial bodies may be considerably 

 modified. 



