communicating. It may be proper, however, to state that a channel or way must previously be prepared, by sinking a series of rods of a peculiar description in the ground, or dropping them in the sea; but these, after the first cost, will remain good for ages to come, if substantial when laid down." 1

From the concluding words of this paragraph it would seem that the Auticatelephor was simply an application to telegraphy of pneumatic or hydraulic pressure in pipes— cautiously styled "rods of a peculiar description." On this supposition the last sentence may be paraphrased thus: "It may be proper, however, to state that a channel or way must previously be prepared, by laying down a continuous series of hollow rods or tubes under the ground or along the sea-bottom." If our supposition be correct, and if Edwards contemplated the use of compressed air, his proposal was certainly novel; but if he designed the use of compressed water, the idea was by no means new. Without going back to the old Roman plan of Æneas Tacticus, we have its revival by Brent and others towards the close of the last century, and the still more practical arrangements of Joseph Bramah in 1796, of Vallance in 1825, and of Jobard in 1827.

PROFESSOR MORSE-1842.

The idea of a wireless telegraph next appears to have presented itself to Professor Morse. In a letter to the Secretary of the Treasury, which was laid before the House of Representatives on December 23, 1844, he says:

"In the autumn of 1842, at the request of the American 1 See also the 'Mechanics' Magazine,' vol. xiii., First Series, p. 182.

Institute, I undertook to give to the public in New York a demonstration of the practicability of my telegraph, by connecting Governor's Island with Castle Garden, a distance of a mile; and for this purpose I laid my wires properly insulated beneath the water. I had scarcely begun to operate, and had received but two or three characters, when my intentions were frustrated by the accidental destruction of a part of my conductors by a vessel, which drew them up on her anchor, and cut them off. In the moments of mortification I immediately devised a plan for avoiding such an accident in future, by so arranging my wires along the banks of the river as to cause the water itself to conduct the electricity across. The experiment, however, was deferred till I arrived in Washington; and on December 16, 1842, I tested my arrangement across the canal, and with success. The simple fact was then ascertained that electricity could be made to cross a river without other conductors than the water itself; but it was not until the last autumn that I had the leisure to make a series of experiments to ascertain the law of its passage. The following diagram will serve to explain the experiment:

“A, B, C, D, are the banks of the river; N, P, is the battery; G is the galvanometer; w w, are the wires along

the banks, connected with copper plates, f, g, h, i, which are placed in the water. When this arrangement is complete, the electricity, generated by the battery, passes from the positive pole, P, to the plate h, across the river through the water to plate i, and thence around the coil of the galvanometer to plate f, across the river again to plate g, and thence to the other pole of the battery, N.

"The distance across the canal is 80 feet; on August 24 the following were the results of the experiment :

Showing that electricity crosses the river, and in quantity in proportion to the size of the plates in the water. The distance of the plates on the same side of the river from each other also affects the result. Having ascertained the general fact, I was desirous of discovering the best practical distance at which to place my copper plates, and not having the leisure myself, I requested my friend Professor Gale to make the experiments for me. I subjoin his letter and the results.1

"NEW YORK, Nov. 5th, 1844.

"MY DEAR SIR, I send you here with a copy of a series of results, obtained with four different-sized plates, as conductors to be used in crossing rivers. The batteries used were six cups of your smallest size, and one liquid

i We omit the tables of results, as of no present value. They can be seen in Vail's book, quoted infra.

used for the same throughout. I made several other series of experiments, but these I most rely on for uniformity and accuracy. You will see, from inspecting the table, that the distance along the shores should be three times greater than that from shore to shore across the stream; at least, that four times the distance does not give any increase of power. I intend to repeat all these experiments under more favourable circumstances, and will communicate to you the results. -Very respectfully, L. D. GALE.

"Professor S. F. B. MORSE,

Superintendent of Telegraphs.'

"As the results of these experiments, it would seem that there may be situations in which the arrangements I have made for passing electricity across rivers may be useful, although experience alone can determine whether lofty spars, on which the wires may be suspended, erected in the rivers, may not be deemed the most practical. The experiments made were but for a short distance; in which, however, the principle was fully proved to be correct. It has been applied under the direction of my able assistants, Messrs Vail and Rogers, across the Susquehanna river, at Havre-de-Grace, with complete success, a distance of nearly a mile." 1

JAMES BOWMAN LINDSAY-1843.

The next to pursue the subject was J. B. Lindsay of Dundee, whose extensive labours in this, as well as in the department of electric lighting, have hitherto been little appreciated by the scientific world. Through the kind. assistance of Dr Robert Sinclair of Dundee, I have lately

1 Vail's' American Electro-Magnetic Telegraph,' Philadelphia, 1845,

collected a number of facts relating to this extraordinary man, and as I believe they will be new to most of my readers, I will draw largely from them in what follows.1

James Bowman Lindsay was born at Carmyllie, near Arbroath, on September 8, 1799, and but for the delicacy of his constitution would have been bred a farmer. At an early age he evinced a great taste for reading, and every moment that he could spare from his work as a linenweaver was devoted to his favourite books. Often, indeed, he would be seen on his way to Arbroath with a web of cloth tied on his back and an open book in his hands; and, after delivering the cloth and obtaining fresh materials for weaving, he would return to Carmyllie in the same fashion. Encouraged by these studious habits, Lindsay's parents wisely arranged that he should go to St Andrews University. Accordingly, in 1821 he entered on his studies, and, self-taught though he had hitherto been, he soon made for himself a distinguished place among his fellow-students, particularly in the mathematical and physical sciences, in which departments, indeed, he became the first student of his time. Having completed the ordinary four years' course, Lindsay entered as a student of theology, and duly completed his studies in the Divinity Hall; but he never presented himself for a licence, his habits of thought inclining more to scientific than to theological pursuits. In the long summer vacations he generally returned to his occupation of weaving, though latterly he took up teaching, and thus enjoyed more time for the prosecution of his own studies.

Coming to Dundee in 1829, he was appointed Science and Mathematical Lecturer at the Watt Institution, then conducted by a Mr M'Intosh. Soon after, Alexander

1 Extracts from the writer's articles in the 'Electrical Engineer,' vol. xxiii. pp. 21, 51.