942 APPENDIX. 



2181c. Model of the Gunfleet Lighthouse. Iron. Built 

 on Mitchell's patent screw piles, of which a model is also shown. 

 The piles screw 40 ft. into the sand, and have screws 4 ft. in 

 diameter. James Walker, engineer. The Trinity House. 



South Kensington Museum. 



2181d. Series of Models, illustrating mark buoys, used by 

 the Trinity House Corporation round the British coast. The 

 Trinity House. South Kensington Museum. 



2181e. Harbour Light. Chance's patent dioptric lens of 

 the fourth order, for fixed light. Chance Brothers and Company, 

 Glass Works, Birmingham. South Kensington Museum. 



2209a. Ship's Light, arranged to show a port, starboard, or 

 anchor light. J. S. Starnes, Broad Street, Radcliff, E. 



South Kensington Museum. 



22O9b. Ship's Lights, port, starboard, and mast head light. 

 Stevens & Sons, Southwark Bridge Road. 



South Kensington Museum. 



2210d. Photographs of the first engine employed on a public 

 railway, of the first and of the most modern railway coaches, and of 

 the first two railway bills. Alfred Marshall. 



2212f. Model of Railway with central rail, 1843. 



Late Baron Seguier, Membre de VInstitut. 



2212g. Model of Central Bail Locomotive with its rail 

 ( 1 842). Late Baron Seguier, Membre de VInstitut. 



2212h. Model of Central Bail Locomotive, by Baron 

 Seguier and Dumery, with part of the road, 1862. 



Late Baron Seguier, Membre de VInstitut. 



2212k. Fog Signal. Edward Alfred Cowper. 



This simple little instrument illustrates the application of the science of 

 acoustics to a very useful object, namely the communication of information 

 from a person on a railway to the driver of a passing train, in a dense fog or 

 on a dark night ; it is the only instrument that accomplishes the object, and 

 has been the means of saving many thousands of lives. Invented by the 

 exhibitor in 1841. 



The principle consists in producing a very different sound from any that is 

 constantly recurring in a railway train, and a sudden explosion or detonation 

 is found to be the best for the purpose ; it is caused by the explosion of a small 

 quantity of gunpowder in a small tin box, by the firing of a match inside which 

 is crushed by the wheel of the passing train. 



2216d. Drawing of Steam Carriage, by the late Baron 

 Seguier, with " sun and planet wheel motion," 1846. 



Late Baron Seguier, Membre de VInstitut. 



