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441 



of experiments made by the Admiralty, under the direction of 

 Admiral Aynsley, and as far as the collection of facts was 

 concerned, nothing could be more conscientious or thorough than 

 that series of experiments ; but as regards proof, they went no 

 further than to show what every experimenter ought to avoid, and 

 how he ought not to conduct his experiments in the future. The 

 author hud placed before the Institution the apparatus then used. 

 It consisted of thirty-eight tubes of iron and steel riveted in 

 metallic contact with the shell of a boiler, and exposed partly to 

 air and partly to hot water and solutions. Although the author 

 had a very poor opinion of electricity and its effects, Dr. Siemens 

 had a strong belief in electricity wherever it had a chance of 

 art ing for good or for evil, and he was convinced that the results 

 obtained in those experiments were rendered entirely unreliable 

 through galvanic agency. The results were most variable. 

 Whereas one iron (common iron seemed to be the best) gave 

 a corrosion of only 7 grains, on an average, per square foot, 

 Bessemer steel gave 21 grains, or three times the amount during 

 the time of exposure. The author was really most merciful when 

 he stated that the result was only 69'3 per cent, in favour of iron, 

 because it was really 300 per cent, in that instance. Notwith- 

 standing these experiments, the Admiralty had adopted a mode of 

 action which seemed strangely at variance with the conclusions to 

 which the experiments would point. They now used steel almost 

 to the exclusion of iron, and he hoped that some one connected 

 with the Admiralty would state the result of more recent experi- 

 ments undertaken with a better knowledge of the conditions under 

 which they should be made. He believed the conclusions since 

 arrived at were very different from those deduced by Admiral 

 Aynsley some years ago. At Table VII. the author had com- 

 pared Landore metal and iron, the one giving an average loss 

 per square foot of 506'24 grains, and the other of 483'1 7 grains, 

 showing a difference of only 4'8 per cent, against the steel, 

 and that was, at any rate, a great deal better than GO per cent. 

 On the same page, the author stated, "The only peculiarity 

 worth noticing in this experiment is that, while the two plates in 

 the feed-water heater lost 381*8 and 394'2 grains, the two in the 

 boiler fed from the heater lost only 8'0 and 3'4 grains respectively." 

 Therefore in the boiler the iron lost by corrosion about one forty- 



