50 ANNUAL OF SCIENTIFIC DISCOVERT. 



several inches it undergoes a violent whipping action, due to the rapid 

 vibration of the double beater upon an axis parallel to its biting and 

 breaking edges ; and aided by the strong currents of air, the shives are 

 still farther removed. The efficiency of the mechanical arrangements 

 of the machine, is shown in the fact that the breaking and whipping 

 action is repeated quietly and safely, at the rate of more than three 

 thousand blows per minute. Such is the perfection of the result, that 

 good well-conditioned flax is delivered from the beater upon the dis- 

 charging apron, in ribbons of fiber, perfect in length and strength, and 

 almost wholly free from woody fragments. The attendant at the 

 discharging end of the machine, gathering two of these layers into a 

 medium sized hand of flax, and favored by the peculiarity in the form 

 of the shives, and the condition in which the fiber is left by the beater, 

 rapidly finishes it upon the scutching wheel. In thi? process much 

 less tow is made than by the old modes, and it is of better average 

 quality, while the condition of the dressed fiber ensures that it will 

 produce less tow on the heckle when manufactured. The machine 

 when worked at a moderate speed, and attended by two hands, will 

 finish from three hundred to four hundred and fifty pounds of flax 

 per day, according to the skill of the workmen, and the quality and 

 condition of the material Aside from the saving in tow, this is fully 

 equal to the average product of the labor of five hands using the 

 common machinery, and, at the rate of speed necessary to accomplish 

 this, about three horse power is sufficient to operate the machine. At 

 a higher speed, from fifty to seventy pounds of fiber can be run 

 though the machine each hour, but it will then require more hands to 

 attend it. The price of these machines is stated to be about $400. 



HOLYHEAD HARBOR. 



ONE of the most stupendous works of modern times, is the great 

 breakwater now constructing by Government for the protection of 

 Holyhead Harbor, on the iron-bound coast of Anglesea, Great Britain, 

 under the direction of Mr. Rendel, C. E. It was commenced in 1849, 

 and is intended to secure a total area of 300 acres for the purpose of a 

 harbor, two-thirds of that space having a minimum depth of seven 

 fathoms at low water. Accommodation will thus be provided for 

 about 400 vessels of all classes, including 70 men of war as large as the 

 Duke of Wellington. The north or great breakwater will be 5,000 

 feet long and 170 feet wide, and of this immense work 4,000 feet have 

 already been completed to low water mark 3,500 feet of it being 

 from 14 to 15 feet above high water. The depth at low water thus 

 filled up is from 45 to 48 feet, and some idea may be formed of the 

 magnitude of this mole from the fact that the stonework which sur- 

 mounts it is about 80 feet above the foundation. The smaller, or east- 

 ern breakwater, which protects the harbor on the landward side, will 

 be 2,100 feet long, and 1,000 feet of it have already been formed, in a 

 depth of 30 feet at low water, and to a width of 100 feet. Since 1849, 

 when the works were begun, 2,400,000 tons of stone, in blocks varying 



