the scientific astronomer alone; for, to state it shortly, until we have the means of affixing accurate numerical values to those forms of vibration which are at present loosely known to us as light, electricity, magnetism, and other imponderable forms of energy, we can only imperfectly avail ourselves in practical life of these wonderful agents in ministering to the wants of mankind.
After dealing with the immensities of celestial space, it is not without an effort that we drag ourselves down to consider matters more immediately connected with our own little planet, less than 8,000 miles in diameter, and one is insensibly led to exclaim, in the language of the old Hebrew Psalmist, "When I consider Thy heavens, the work of Thy fingers, the moon and the stars which Thou hast ordained, what is man that Thou art mindful of him, or the son of man that Thou visitest him!" Yet, in our present state of existence, it is unavoidable that our minds should be mainly occupied in attending to the ways and works of our fellow-men upon this sublunary sphere.
ENGINEERING.
The year is marked by the completion of great feats and the commencement of fresh efforts in engineering. The geological difficulties which for some time seemed insuperable to the completion of the San Gothard Tunnel have been overcome, and another route, which may be of some importance both as regards passengers and the mail service, has thus been opened between Australasia and England. The great canal that is to cut the Isthmus of Panama is in process of construction, and a second Suez Canal is contemplated. Tunnels have been commenced under both the Severn and the Mersey, and, were it not for political considerations, the great scheme of connecting England with the Continent would no doubt be speedily progressing. The Frith of Forth is being bridged over by what will be, when completed, the boldest structure of the kind throughout the world, with gigantic spans of no less than 1,700 feet.
ELECTRICITY.
But the subject which at present commands most attention in the scientific world is the use of the electric current; and it may be well to note here how far we have now advanced in the various ways of utilizing this marvellous instrument. One of the chief obstacles for many years to the use of electric force was the great cost of producing an electric current so long as chemical means had to be resorted to. This has been overcome by the invention of the dynamo-machine, which has been brought to such a state of perfection that by it we are enabled to convert mechanical into electrical force, and back again
