Page:Popular Science Monthly Volume 45.djvu/492

474 this amount of material removed from the crowns of a few high hills in the vicinity would alter the landscape considerably, and that this alteration, together with the turning of the Irish Sea into a landlocked bay, might confuse a person acquainted with the locality only as it had been before the commencement of the work. The territory to be acquired for the land work would not be expensive, as the country on both sides is almost desert.

It is proposed to construct two generating plants near the two shores respectively, each to be used to supply the country to which it is nearest. In order not to interfere with navigation, it is suggested to enlarge the canal of Crinan and to make a cut through the isthmus of Tarbert. To the writer it does not seem that these means would be better than simply to cut through the dam and provide suitable locking facilities.

One of the remarkable results which, it has been pointed out, would flow from the construction of such an artificial isthmus is the lowering of the level of the Irish Sea along the east coast of Ireland, and thus rendering the marsh lands in that section capable of receiving a high degree of cultivation.

Besides the great interest that any such plan must have in itself, from the fact of the important change in the geography of the British Isles which it would bring about, the results that would flow from a utilization of a part of the tidal power for distribution throughout the kingdom are most impressive. Our means for the distribution of power electrically have developed, within the past year or two even, to an extraordinary degree. Two years ago it was possible to transmit electricity for lighting purposes a great number of miles from the point of generation, but it was not commercially possible so to distribute electricity for power purposes. The reason for this is that in order to have electricity in a safe form for use in houses, mills, or car lines it must be supplied at low voltage (or electrical pressure); on the other hand, if we are not to use an utterly prohibitive weight of copper conducting wire we must transmit at high voltage. What is done, therefore, is to transmit at, say, ten thousand volts and transform at the consuming end down to anywhere from five hundred to one hundred volts; the trouble is that there is no practical way of transforming direct currents, and until recently the alternating could not be used to work commercial motors. Now, however, due largely to the work of Mr. Nikola Tesla, we have motors that operate at very good efficiency on alternating circuits. The methods of insulation and of polyphase transmission have, moreover, been improved greatly within a year or two, and these have brought up the capabilities of the wire both for carrying more current and working at higher voltage than was before the case. In the present state of the art it would be safe for an electrical engineer