Thomas Jefferson Papers

Marcus Dyson to Thomas Jefferson, 6 May 1816

From Marcus Dyson

Richmond May 6. 1816

Dear Sir

I hope you will pardon the liberty I have taken in addressing you, I have no other apology to offer except total unacquaintance with any person who could give me the information I desire, the eminent rank you hold in this Country, your acquaintance in Europe, & great reading, led me to hope you could, my enquiry is this,

whether oxygen gas can be pressed with same facility as atmospheric air,

whether the extreme pressure will not destroy its vitality, &

whether the passage of the expired air through the water, will absorb the carbon & render it fit for inspiration—

however to shew you I do not propose questions without a reason, I shall Subjoin a drawing of a machine, to be used by a person wishing to travel under the water, So as to leave his arms & legs at perfect liberty. this is but the outline of a machine, on which many improvements may be put & many alterations made for the better. I have taken the Standard of pressure @ 20 times & allowing 1 pint for inspiration & 20 pr minute 110 consumed would be the actual consumption of 1 Quart pr minute, therefore this reservoir would support life 80 minutes. but this could be varied to any length of time by enlarging or contracting the reservoir the same principle applies to the pedestrian & boat Navigation, the whole question rests upon the above 3 points, & if they can be established, what a vast feild will be opened for Speculation, what immense advantages will mankind derive from the discovery, no longer can proud Navies approach our Shores and fill our Bays with impunity, nor the hidden treasures of the ocean remain undiscovered—

It has for a long time been considered a desidetarium, by me, to enjoy equal privileges with the inhabitants of the Ocean, on foot to explore the bottoms of our Bays & Rivers, or to navigate them & the ocean beneath the surface in boats. both of which I think I have accomplished,1 & though I can have but little doubt on the Subject, Still the impossibility of procuring Suitable apparatus for the purpose of making experiments in this City, induced me to lay the whole plan before you (& you are the only person who knows it) & not only request your reply to my queries, but your advice & opinion upon the whole business, which will determine me in the further prosecution of it, I should be much more lengthy in my communication, were I not afraid of occupying too much of your time. your reply as Soon as convenient will much oblige

Your mo Obt Svt—

Marcus Dyson

RC (DLC); addressed: “His Excellency Thomas Jefferson Monticello Albemarle Virginia”; franked; postmarked Richmond, 10 May; endorsed by TJ as received 13 May 1816 and so recorded in SJL; with enclosure on both sides of address cover.

1Manuscript: “accomplised.”

Index Entries

  • Dyson, Marcus; letter from search
  • Dyson, Marcus; underwater breathing apparatus of search
  • inventions; diving apparatus search