Pine Bluff daily graphic., 1898-08-14

| marine topedo boat was the invention of David Bushnell, of Saybrook, Conn. It was built in 1725, though Bushnell appears to have been working on the idea for many years prior to that.
 Of the public men of the day, Thom- as Jefferson alone seems to have taken an interest in the boat, for the only complete description of it is to be found inaletter which Bushnell wrote to him under date of October, 1787, in which he fully described the construction and operation of his unique craft.
 This description is most minute and detailed, but in view of Hollands much discussed submarine boat anG the in terest all classes, save government off cials, have taken in it, the letter is worth while reproducing in part. It is as follows:
 ''The external shape of the submarine boat bore some resemblance to two up per tortoise shells, joined together the fue or entrance into the vessel being represented by the openings made by the swells of the shells at the head. of the animal. The inside was capable of containing the operator, and air suf1i- 1 cient to support him for 30 minutes, without receiving fresh air. At the bottom opposite to the entrance was fixed a quantity of lead as ballast, at one edge. Directly before the opera tor, who sat upright, was an oar for rowing backward or forward. Atthe other edge was a rudder for steering. i An aperture, at the bottom, with its valves, was designed to admit water, for the purpose of descending, and two l brass forcing pumps served to eject l the water within when necessary for ascending. At the top there was like wise an oar for ascending OF descend l ing, or continuing at any particular depth. A water gauge or barometer determined the depth of the descent, a compass directed the course, and ventilator within supplied the vessel with fresh air when on the surface.
 "The entrance into the vessel was elliptieal and so small as barely to ad init one person. This entrance was surrounded by an iron band, the lower edge of which was let into the wood of which the body of the vessel was made in such q manner a s 70 give it's utmost support to the body of the yes sel against the pressure Of the water. Above the upper edge of thiairoH band 1 there was crown or cover resembling hat, with it's crown and brim, which shut water tight upon the iron band. The crown was hung 10 the iron band with hinges 70 turn over edgeways when opened. To make 1t perfectly se- cure when shut it might be screwed down upon the band by the operator, OF by a person within.
 "There was in the brass crown three round doors, one directly in front, and one on each side large enough to put the hand through. When open they ad- mitted fresh air. Their shutters were ground perfectly tight into their places when shut. There were likewise several glass windows in thecrown for looking through and for admit ting light in the daytime, with covers to secure them.
 '"There were two air pipes in the crown, a ventilator. which drew fresh air through one of the pipes ard dis charged it into the lower part of the vessel. The fresh air introduced by the ventflator expelled the impure air through the outer pipe. Both air pipes were so constructed that they shut themselves whenever the water rose near their tops, so thatno water could enter through them.
 "The vessel was chiefly ballasted with lead fixed to it's bottom; when there was not sufficient, quantity was placed within, more or less, according to the weight of the operator. lis bal last rendered it so solid there was no danger of it's oversetting. The vessel with all of it's appendages and the op- orator was of a sufficient weight to set tie it low in the water About 200 pounds of lead at the bottom for bal last could be let down 40 or 50 feet be- low the vessel This enabled the opp orator to rise instantly to the surface of the water in case of accident.
 sWhen the operator desired to de- scend he placed his foot upon the top of the brass valve, depressing it, by which he opened large aperture in the bottom of the vessel, through which the water entered at his pleas ure. When he had admitted certain quantity he descended very gradually If he admitted too large quantity, in order to obtain an equilibrium he eiected as much as was necessary by the two brass forcing pumps. which were placed at each end; whenever the vessel leaked, or he desired to ascend 10 the surface, he also made use of the forcing pumps.
 When the operator had obtained an equilibrium he could row upward or downward, or continue al any particu- lar depth, with all oar placed near the top of the vessel, formed upon the prin- ciple of screw. By turning tie oar in one direction he raised the vessel; by turning it in the other way he de- pressed it.
 "A glass tube eight inches long and one inch in diameter, standing upright,