The Crystal Porcelain Pottery Company exhibited telegraphic and electrical insulators

THE INTERNATIONAL ELECTRICAL AND GAS EXHIBITION.

TOWARDS the close of last year we published a notice of the International Electrical and Gas Exhibition which is now being held in the Crystal Palace. At the time of our notice the exhibition generally was in a very backward condition, particularly the electrical section. Since then great progress has been made, and upon the occasion of a recent visit we found the exhibition generally complete. We now purpose giving a notice of such exhibits as were previously in an incomplete state, and for this purpose we shall have to repeat ourselves to a limited extent. Besides these, we shall notice such matters of merit as have come under our notice since our previous article. We may observe that the display of electric lighting is a comparatively poor one, whilst there is a very profuse show of gas lighting. The reason why so meagre a display of electric lighting is being made is said to be due to the circumstance that the leading electrical companies are too full of business to need to further advertise themselves at present. The electricians are in possession of the north nave mainly, whilst the gas interests are well represented in the south nave. Turning first to the electrical portion of the exhibition, we may first notice one of the best examples of electric lighting, which is to be seen in the Alhambra court, which is situated at the far end of the north nave.

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Electrical and telegraphic apparatus of almost every kind and the various accessories of electrical science are to be found at a series of stands arranged down the center of the north nave. Amongst them, however, are but few novelties, although the contents of the stands are for the most part generally interesting. One of the chief exhibits possessing both novelty and interest is to be found at the stand of the Electrical Trading Company, who exhibit samples of MM. Berthoud Borel & Co. s electric conductors, which are a wide departure from ordinary practice, and were recently described and illustrated by us. The conductor is formed of a copper wire, or several if necessary, wrapped with several thicknesses of cotton and then plunged into a bath containing the insulating material. The protected wires are then encased in lead by an ingenious and special process, which consists in compressing an ingot of lead by means of hydraulic apparatus, forming it into a tube, and drawing it over the wire which has been coated with the cotton and the insulating material. This method of manufacture enables the conductors to sustain a high temperature without damage, and they are favourably reported upon in other respects. The Crystal Porcelain Pottery Company exhibit some telegraphic and electrical insulators, which possess a remarkably high degree of vitrification, as shown by the fractures, and which quality especially adapts them for their purpose as insulating media. Mr. H. R. Meyer shows a new system of underground permanent way for electric conductors, which is described and illustrated at page 224, vol. xx. of IRON. It consists of slabs of earthenware made with a series of parallel grooves. These slabs are laid end to end, and the naked wires are laid in the grooves. Asphalte is then poured over the slabs and grooves, and the whole thus insulates the wires. In order to economise space in practice these slabs are to be laid tier above tier, and to further secure the wires from all possible chance of injury, a number of them are to be laid in a cast-iron channel. By these means a large number of wires can be laid in a comparatively small space, as evidenced by the examples shown. In view of the increasing number of telegraph and telephone wires which are to be seen overhead in most towns, and the consequent increase of danger, Mr. Meyer's system is worthy of consideration. Messrs. Le Grand & Sutcliff exhibit a very useful dwarf pile, or stem and rammer for the foundations of telegraph posts and electric lamp standards. There are a number of stands at which medical electricity is well represented.

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