THE CEDARS OF LEBANON.--Regulations were lately issued by Rustem Pasha for the guidance of travelers and others visiting the Cedars of Lebanon. These venerable trees have now been fenced in, but, with certain restrictions, they will continue to be accessible to all who wish to inspect them. In future no encampments will be permitted within the enclosure, except in the part marked out for that purpose by the keeper, nor may any cooking or camp fires be lighted near the trees. * * * * * ON THE MECHANICAL PRODUCTION OF ELECTRIC CURRENTS. The object of these articles is to lay down in the simplest and most intelligible way the principles which are concerned in the mechanical production of electric currents. Every one knows now that electric lights are produced from powerful currents of electricity generated in a machine containing magnets and coils of wire, and driven by a steam engine, or gas engine, or water-wheel. But of the thousands who have heard that a steam engine can thus provide us with electric currents, how many are there who comprehend the action of the generator or dynamo-electric machine? How many, of engineers even, can explain where the electricity comes from, or how the mechanical power is converted into electrical energy, or what the magnetism of the iron magnets has to do with it all? Take any one of the dynamo-electric machines of the present date--the Siemens, the Gramme, the Brush, or the Edison machine--of each of these there exist descriptions excellent in their way, and sufficient for men already versed in the technicalities of electric science. But to those who have not served an apprenticeship to the technicalities--to all but professed electricians--the action of these machines is almost an unknown mystery. As, however, an understanding of the how and the why of the dynamo-electric machine or generator is the very A B C of electrical engineering, an exposition of the fundamental principles of the mechanical production of electric currents demands an important place in the current science of the day. It will be our endeavor to expound these principles in the plainest terms, while at the same time sacrificing nothing in point of scientific accuracy or of essential detail.