The famous Blind Engineer of Belfast. 23 



additional years, a circumstance almost without precedent, testi- 

 mony having been given in its favour by all the principal engineers 

 of the day. 



A dock on the plan above alluded to has never yet been con- 

 structed, but the screw pile and screw moorings are now extensively 

 used in many lands, a new and valuable principle being afforded by 

 their means to engineering enterprise. 



The foundation of the first lighthouse was put down in the 

 summer of 1838, on the Maplin Sands, a very unstable bank near 

 the entrance of the Thames, for the Corporation of Trinity House 

 of Deptford and Stroud. This foundation consisted of nine wrought 

 iron piles, with a four feet screw at the foot of each, placed in the 

 form of an octagon, with one in the centre, and screwed into 

 the bank to the depth of twenty-two feet, in nine consecutive 

 days. But the first house of the kind that was lighted was at 

 Fleetwood, on Wyre. The lighthouse was planned and executed 

 from his own design, by himself, with the assistance of his son, 

 during the winter of 1839. 



After that time Alexander Mitchell, with the assistance of his 

 son, applied the same principle to the building of lighthouses, piers, 

 beacons, etc. In 1862, Mitchell, being in his eighty-second year, 

 retired from active life, but had the satisfaction of knowing that his 

 screw piles and moorings were conferring important benefits on 

 India and on America, both North and South. 



One autumn there were some very stormy days, and in the 

 twilight hour as he lay resting on the couch, during intervals in the 

 almost constant reading, he pondered much on the trials of ship- 

 wrecked men, and pictured their difficulties as he listened to the 

 wind that raged round the cottage. He said that he set his mind 

 determinedly to work to think out some means of warning for ships 

 that are in danger from rocky shores. 



In 1832 his thinking brought him some very original ideas, and 

 one of them he carried out with the help of his son John, then a 

 lad of about 19. 



This son afterwards described the first experiment as of a most 

 exciting nature. As the evening dusk came on he and his father 



