Gtniral Principhs and ConjlruBion of a Sub-marine Vejfet. ft? j 



IK. 



Gtmral PtincipUs and ConJlruBion of a Sub-marine Vtjfel, co7nmunicaUd by D. Bushnell, 

 of ConneSicui, the Inventor, in a Letter of 08ober, 1787, to Thomas Jefferjon, then 

 Minifler PUnipoientiary of the United States at Paris* 



X. HE external fliape of the fub marine veflcl bore fome rcfemblancc to two upper 

 tortoife fliells of equal fize, joined together; the place of entrance into the veflel being 

 reprefentcd by the opening made by the fwell of the (hells, at the head of the animah 

 The infide was capable of containing the operator) and air, fufhcient to fupport him thirty 

 minutes without receiving frefii air. At the bottom oppofite to the entrance yiras fixed a 

 quantity of lead for ballaft. Atone edge which was dire£t!y before the operator, who 

 fat upright, was an oar for rowing forward or backward. At the other edge, was, a 



* Tranfaftions of the American Philofophical Society. IV. 303. 



Tiiis is tlie only modern' inftance I am acquainted with of the purfuit of Aib-mat'ine navigation. The 

 Aibjefl was largely and pleafantly defcanted upon by Merfennus in his TraQatus de Magnetu Profrieta- 

 tibus, and Bifliop Wilkins has given a chapter at fome length on the fame fubjeft, in his Matkematicat 

 Magick. (ed. 1648) where he affirms, that Cornelius Dreble had proved, beyond all quertion, that 

 the contrivance is feafible by the experiments he made in England. The chapter of Wilkins is enter- 

 taining for a fort of vifionary facility with which he rtmoves the difficulties and enumerates the benefits of 

 thefe fub-marine enterprizes. For letting out and taking in fuch things as the nature of the voyage may 

 require, he recommends bags, or flexible tubes, fomewhat refembling the fcuppcr bags of (hips. The 

 ;progreffive motion may, he obferves, be produced by fins or oars, which will operate with eaf« when the 

 ..TefTel is truly equipoifed, and if fwiftnefs Ihould not be obtained, he fuppofes, the obfervations and difco- 

 teries to be made at the bottom of the faa would abundantly recompence for that defeft. The greateft 

 difficulty, in his apprehenfion, would be in the neceffity of renovating the air for refpiration and com- 

 buftion i for remedying which, befides the probability that cuftom may render men capable of living in air 

 of inferior purity, he has feveral philofophical views and projefls. The conveniencies and advantages 

 -he enumerates, are, 1. Privacy; as a man may thus go to any part of the world invifibly, without 

 ibeing difcovered or prevented. 2, Safety; from the uncertainty of tides and tempefts which vex the fur- 

 face; from pirates and robbers 5 and from the ices which fo much endanger other voyages towards the 

 poles. 3. It,m»y be of ufe to undermine and blow up a navy of enemies ; 4, Or to relieve a blockaded 

 place : 5. And as the profpeft enlarges in the mind of our author, he proceeds to contemplate the unlpeak- 

 able benefit of fub-marine difcoveiies. Experiments on the afcent and defcent of fubmerged bodies ; the' 

 exploration of the deep caverns and pafTages of the waters of the ocean;, obfervations on the nature a3)d 

 , kinds of fifbcs,- with the allurements, artifices, and treacheries, which may fuccefsfully be practiced 

 during fo familiar a refidence in their territories ; the food and oil they may afford ; the probability of 

 firefli fprings for a fupply of w.iter at the bottom of the fta ; the facility of recovering fub-marine tieafufcs 

 whethsr loft or naturally produced beneath the ocean ; and laft of all he adds, that 



" All kinds of .arts and nianufaftures may be exercifed in this vefTel. The obfervations roade by it may 

 " be both written, and (if need were) printed here likewife. Several colonies may thus inhabit, having 

 •" their children born and bred up without the knowledge of land, ivbo auld not cbufe but be amaxtd 

 *' with ftrange (onuitfufea the di/co-veiy of this uffer lUdrW." 



rudder 



