Page:Ballantyne--The Battery and the Boiler.djvu/76

 This core, when completed, was wound in lengths on large reels, and was then submerged in water and subjected to a variety of severe electrical tests so as to bring it as near as possible to a state of perfection, after which every inch of it was examined by hand while being unwound from the reels and rewound on the large drums on which it was to be forwarded to the covering works at East Greenwich, there to receive its external protecting sheath.

All this, and much more besides, did Robin Wright carefully note down, and that same evening went home and delivered a long and luminous lecture, over which his mother wondered, Madge rejoiced, his father gloried, and uncle Rik fell asleep.

Next day he hastened to the covering works, and, presenting his credentials, was admitted.

Here he saw the important and delicate core again carefully tested as to its electrical condition, after which it received a new jacket of tanned jute yarn to protect it from the iron top coat yet to come. Its jute jacket on, it was then coiled away in tanks full of water, where it was constantly kept submerged and continuously tested for insulation. Last of all the top coat was put on. This consisted of ten wires of peculiarly fine and strong iron. Each of these ten wires had put on it a special coat of its own, made of tarred Manilla yarn, to protect it