100 ANNUAL OF SCIENTIFIC DISCOVERY. 



with this advantage over a rivet, that when required it may be moved 

 from its place without any trouble. It is well adapted for the frame- 

 work of locomotives and railway carriages. The bolt passes through 

 an iron frame, or through wood-work, and is secured behind by a nut. 

 But inasmuch as a nut is liable to be unturned in the extremity of 

 the thread of the screw-bolt by vibration, and as many railway acci- 

 dents have happened from the fact of bolts having parted for the 

 want of their retaining nuts, in the present case the nut is kept in 

 its place by having a spring inserted into it, which adapts itself to the 

 ratchet-work of a hollow washer. 



NEW SEA-ISLAND COTTON-GIN. 



The ginning of sea-island cotton has always been a difficult me- 

 chanical achievement; the ordinary cotton-gin of Whitney injuring 

 the long and delicate fibres too greatly to admit of its use. A gin, 

 known as Brown's Excelsior gin, invented in 1858, but recently intro- 

 duced for use, seems to overcome all the difficulties heretofore expe- 

 rienced by inventors in this department. It consists of a single roller, 

 a steel breastplate, and a vibrating stripper, by which the seeds are 

 thrown down behind and through a grating, while the cleaned cotton 

 is delivered in front. To present some idea of its construction and 

 operation, we will state that it closely resembles a box about three 

 feet in height, three feet in width, and the same in length. In front 

 and on the top is a leather-covered wooden roller, about five inches in 

 diameter, and thirty-six inches in length. The leather with which it 

 is covered is formed of strips two inches in width, wrapped spirally 

 around it, tacked down at the edges, and bevelled so as to form a 

 spiral groove from end to end. Behind this roller is a steel breast- 

 plate, closely resembling a broad and long shaving-knife of exquisite 

 and peculiar temper. The edge of this plate presses close against the 

 back of the roller, and above it, extending across, is a vibrating or 

 stripping bar, which plays up and down like the crosshead of a saw- 

 gate. Behind this is the feed-board, which has an iron grating situa- 

 ted close to the breastplate. The uncleaned cotton is placed on the 

 feed-board, and is pressed forward in a stratum by the girl that attends 

 the gin. The machine is driven by band and pulley, the roller rotates 

 downward toward the steel breastplate, and draws the fibre of the 

 cotton between the roller and the steel plate. There is not sufficient 

 space for the seed to pass through between the roller and the breast- 

 plate scraper; therefore the seed is left behind, and the vibrating 

 stripper strikes down upon it, executing a series of small blows which 

 knock off the seed, driving it through the grating, and into a recep- 

 tacle below the feed-board. The uncleaned cotton goes into the gin 

 behind, a mass of black and white knots ; it comes out in front a 

 beautiful, white, silky-looking fibre. A cord, is stretched in front from 

 side to side across the roller, to prevent the cotton from being carried 

 around and clogging the gin. When a gin is first started, the ginned 

 cotton drops from the roller freely, but after running for a short period 

 the roller becomes so positively charged with electricity, that the cot- 

 ton is attracted to it, and would be carried round and round but for 

 the stripping-cord in front. One of these gins will clean from two 



