Citizens, yesterday on my return from Brest I received your note, and will with pleasure communicate to you the result of my experiments, during the summer, also the mode which I conceive the most effectual for using my invention against the enemy. Before I left Paris I informed you that my plunging boat had many imperfections, natural to the first machine of so difficult a combination, added to this I found she had been much injured by the rust during the winter in consequence of having in many places used Iron bolts and arbours instead of copper or brass, the reperation of those defects and the difficulty of finding workmen consumed near two months. And although the machine remained still extremely imperfect yet she has answered to prove every necessary experiment In the most satisfactory manner. On the 3d of thermidor I commenced my experiments by plunging to the depth of 5 then 10 then 15 and so on to 25 feet but not to a greater depth than 25 feet as I did not conceive the Machine Sufficiently Strong to bear the Pressure of a Greater column of water, At this depth I remained one hour with my three companions and two candles burning without experiancing the least inconvenience. Previous to my leaving Paris I gave to the Cn. Gueyton member of the Institute a calculation on the number of cube feet In my boat which is about 212 in Such a Volume of Air he calculated there would be sufficient Oxszine to nourish 4 Men and two small candles 3 hours. Seeing that it would be of great Improvement to despence with the candles I have constructed a Small window in the upper part of the Boat near the bow which window Is only one inch and a half diameter and of Glass 9 lines thick, with this prepared I descended on the 5th of thermidor to the depth of between 24 and 25 feet at which depth I had Suffecient light to count the minuets on the Watch, hence I conclude that 3 or 4 Such windows arranged in different parts of the boat would give suffecient light for any operation during the day each window may be Guarded by a Valve in Such a manner that Should the glass break the Valve would immediately Shut and Stop out the Water, finding that I had air and light Suffecient and that I could Plunge and Rise perpendicular with facility. On the 7th Ther^d I commenced the experiments on her movements. At 10 in the Morning I raised her anchor And hoisted her Sails which are the Mainsail and Gib the breeze being light I could not at the Utmost make more than about two thirds of a league per hour. I tacked and retacked tryed her before and by the wind And in all these operations found her to Answer the helm And Act like a common dul Sailing boat, After exersising thus About An hour I lowered the mast and Sails and commenced the operation of Plunging this required about two Minuets. I then placed two men at the engine which gives the Rectileniar Motion, And one At the helm, while