was built by Messrs. Laird, of Birkenhead, and launched in 1838; she was 70 ft. in length, 10 ft. wide, and drew 6 ft. 9 in. of water."

From the foregoing extracts, your readers will very clearly see that the "History" puts the merits of successfully introducing the screw, in the following order :

To Ericsson is assigned the merit of being the first man to have a boat built by Gulliver, and, with this peculiarity, that she was fitted with two propellers, each 5 ft. 3 in. in diameter, while the said boat drew 2 ft. 3 in. of water; that the same boat towed the American packet-ship, Toronto, &c.; and that it was only when these experiments were being made by Ericsson that Thomas Pettit Smith obtained his patent for a sort of screw, and built his boat of 6 tons burthen, with a cylinder of 6 in. diameter, &c.; also, that after witnessing the experiments made by Mr. Ericsson, in the Francis B. Ogden, and his towing the Toronto, Capt. Robt. F. Stockton, ordered two large vessels from Ericsson, and that the first of these was built by Messrs. Laird, in 1838, and took her owner's name.

Now, Sir, let me bear witness to the above record, and the stated order of things, being altogether in error. The facts of the case, and I write them from an anxious, laborious, and costly experience, are as follows:

I know a boat was built by Gulliver-by the order of, and for Francis Pettit Smith-she was about the dimensions named, and drew 2 ft. 3 in. water. She had a screw of true and proper form, 2 ft. in diameter. This screw can yet be seen lying in the South Kensington Museum; she did not attempt to tow anything larger than a barge.

It was while these experiments were being carried out by Smith, in 1836 (Smith's patent for a true-formed screw, bearing date 31st May in that year), that Ericsson obtained his patent, not for a screw, but for propellers made of hollow cylinders with blades upon their circumference; two of these were to be used in each vessel, and they were to work abaft the rudder, according to his patent No. 7,149, and dated 13th July, 1836. Figs. 1 and 3 give a representation of his patented improvements, and are cut from his own specification.

The boat built to test Ericsson's propellers was the Robt. F. Stockton ; she had them fitted abaft the rudder, as shown in Fig. 4, and they were about 5 ft. 3 in. in diameter. It was this boat which towed the Toronto. But this test was not made until the year 1839, and even then not a-stern, as stated in the "History," for owing to the Robt. F. Stockton's propellers being abaft her rudder, she steered so badly, that she had to be lashed alongside of the Toronto. I was personally witness to this trial, and may therefore speak with confidence. After many other tests, and several alterations, the Robt. F. Stockton was taken under sail power to America.

To carry the subject to another stage, I will again refer to the History," page 107. It states, "The first successful application of this screw-propeller on a large scale was to a vessel called the Archimedes, constructed under the direction of the patentee of the screw, Mr. Smith. Her screw-propeller consisted of two half-threads of an 8 ft. pitch, 5 ft. 9 in. diameter, &c." In the footnote, on⚫ page 109, is stated, "The first experiment of the Archimedes was made on Monday, Oct. 14, 1839."

The "History omits mention of many important circumstances in connection with the Archimedes, especially those leading up to her being designed and built by myself, and wrongly states several of those it attempts to give. Amongst these latter I may point out that her propeller consisted of one blade, or thread, extending the whole turn round the shaft, 8 ft. pitch, and 7 ft. in diameter, and that her first trials were (not in October) in May, when two great events occurred. The first was on the 14th May; the Archimedes went round to Portsmouth at the launch of the Queen, 120 guns, and on May 26, 1839, when on another of her trials, she exploded her boiler in the East India Docks.

As I believe I was perhaps the most active and practical mover in successfully introducing the screw, I feel sure you will kindly assist me by publishing this letter, and thereby enable me to assert for myself the share or degree of merit attaching to my earlier labours. In June, 1872, you very ably and kindly wrote, supporting my claim and title in this

matter.

It was in the early part of the year 1838 that I first had to do with Smith's little boat. She had prior to this been under the notice and tests of engineers and others, and was fully and formally condemned by a committee which had been appointed to report upon the invention. Her screw consisted of a whole turn round the shaft, and was situated in a hole cut in the body of the boat, about one-fifth her length from aft. Her engine was of the ordinary table type, with a single cylinder 9 in. diameter. It was situated before the propeller, and its power was communicated to the propeller by a third, or vertical shaft, and bevelled wheels. This was the unpromising state of affairs when I was first introduced to them. After making an examination of all the conditions, I clearly saw that when all the absurd surroundings were removed, and the screw properly fitted, shaped, and driven, it must be a success. Consequently I arranged a meeting of my friends, consisting of Lord Weston, Admiral Wollaston, Messrs. Wright, Cauldwell, Wollaston, and others. To these gentlemen I gave my opinion that the screw, if properly applied, would supersede the paddle-wheel. I supported this opinion by offering to subscribe £500 towards building a larger and suitable vessel. Before separating, my friends added a further £5,000,

and in three days afterwards this sum had been increased to £15,000. I then commenced to build the Archimedes.

Francis Pettit Smith, afterwards Sir Francis Pettit Smith, and his surveyor, Mr. Thomas Pascoe, were also retained by the company to prepare and approve the necessary drawings, and these drawings are fairly represented in Fig. 1, the screw being placed in a kind of well :

FIG. 1.

SMITH'S Patent Screw Propeller, May, 1836, and his Plans proposed for the Experimental Vessel called the Archimedes, May, 1838.

The system of bulkheads, before and abaft the propeller, being still retained. I objected to the plans; and it was only after calling a

Before Ericsson's Patent.

meeting of the directors of the company that I succeeded in obtaining permission to finish her, as shown in Fig. 2:

Fig. 2.

WIMSHURST'S Patent Improvements, and his Screw, finally adopted by the Ship Propeller Company,
1838-9.

Thus completed, she was launched in October, 1838, her propeller having one whole turn, as shown in Fig. 1. We had several trials in May, 1839, and it was found that the propeller caused very considerable vibration in the stern of the vessel. When starting on one of these trials, on May 26th, the boiler exploded. While the boiler was under repair, and in August, 1889, I obtained the directors' consent to make a propeller of two blades, each having a half turn only, 10 ft. pitch, and