14 



SCIENCE 



[Vol. VI., No. 126. 



members ; and the proceedings were opened on Tues- 

 day, June 23, by the reading of a very interesting 

 paper by Mr. E. B. Dorsey, entitled 'English and 

 American railroads compared.' It appears that the 

 average cost of the English railroads has been $202,- 

 227 per mile, as against $62,176 for the American 

 roads. At six per cent, to justify this increased ex- 

 penditure, that part of the operating expenses which 

 is affected by good or bad construction should involve 

 a saving of about $8,000 per mile per year in the 

 case of the English roads. The comparisons of the 

 writer showed that this was by no means the case, 

 the saving being rarely over $1,000. Comparisons of 

 this kind, however, cannot pretend to be more than 

 approximations, as the items of expense cannot always 

 be accurately separated ; and, moreover, the figured 

 cost of English roads probably includes the cost of 

 parliamentary proceedings in obtaining the charter. 

 Kegarding the physical characteristics of the English 

 roads, few of them attain elevations of nine hundred 

 feet above the sea; and their construction, therefore, 

 offered few engineering difficulties, their greater first 

 cost having been due to the almost entire absence of 

 temporary structures. Recently several miles had 

 been laid with steel sleepers, weighing a hundred and 

 twenty-four pounds, on the London and north-western 

 railway, following the example of the German roads, 

 where tliey are quite common. Of freight-cars, only 

 about twenty per cent have brakes in England; and 

 these are so placed that they cannot be operated 

 when the train is in motion : so the only effective 

 ones are those on the engine and caboose. And in 

 passenger-tiains, where the air-brakes are used, but 

 where only one car in three or four has a hand-brake, 

 plat form-cars heavily loaded with cast-iron, and 

 provided with powerful hand-brakes, are attached on 

 steep grades, to hold the train in case of accident to 

 the air-brakes. 



Prof. T. Egleston of New York presented an 

 interesting paper on the cause and prevention of the 

 decay of building-stones. In the speaker's investi- 

 gation of the decomposition of calcareous materials 

 due to the action of city gases and rain-water, he 

 had found that the action was a maximum at a height 

 of ten feet above the ground, above which point it 

 decreased, and was null above a height of a hundred 

 feet. To prevent decay, the only remedy was to 

 make the stone water-proof. The speaker believed 

 that a wash of sulphur was the only thing of value, 

 where the stone was a dolomite, according to some 

 experience in England. In the case of all porous 

 stones, he considered that an effectual remedy would 

 be to immerse the stone in boiled linseed-oil, renew- 

 ing the application until the stone was saturated. 

 Some discussion on this paper took place, many mem- 

 bers believing that the use of oil would prevent the 

 formation of a good bond between the stones and the 

 mortar. It was stated, however, that the method 

 had been tried with success in England. 



A valuable and extensive report was presented by 

 the committee on the preservation of timber, whose 

 work lias covered five years. It appears from the ex- 

 perience in this country that Kyannizing, or treat- 



ment with corrosive sublimate, though of value when 

 the wood is only exposed to occasional moisture, is 

 not efficacious when the wood is permanently wet. 

 Although the testimony obtained was somewhat con- 

 flicting, the committee recommended the process of 

 Burnettizing (chloride of zinc) as the best process 

 for preserving railroad ties, principally on account of 

 the low cost, which was only from twenty to twenty- 

 five cents a tie. Creosoting was found too expensive ; 

 although it is the only effectual method for wood ex- 

 posed to the attacks of the teredo and limnoria, and 

 is, without doubt, the most generally successful pro- 

 cess. In connection with this report, a report was 

 presented by Mr. F. Collingwood, on the preserva- 

 tion of forests. 



A paper followed by Mr. Jos. M. Wilson of Phil- 

 adelphia, on specifications for iron and steel railroad- 

 bridges, which was succeeded by a long discussion 

 regarding the cantilever bridge at Niagara Falls, on 

 which a paper had previously been presented to the 

 society. The specifications for this bridge, in which 

 steel was used for all the principal compression mem- 

 bers, provided for the use of open-hearth steel alone. 

 In this discussion the opinion was very generally ex- 

 pressed that Bessemer^ steel should not have been 

 barred out, and that in drawing up specifications the 

 engineer should insist simply on a certain quality as 

 determined by physical tests, leaving the manufac- 

 turer free in the method of manufacture. It is prob- 

 able in this case, however, that Bessemer steel was 

 excluded to prevent delays in getting steel from works 

 that had not had experience in making steel for 

 structural purposes, as most of the Bessemer works 

 had been making rail steel, and not structural steel. 

 The fact that in making the steel for this bridge a 

 hundred and thirty-six beats out of two hundred and 

 forty-five were rejected, showed, in the opinion of 

 many members, that engineers were requiring too 

 much of steel, that the specifications were too rigid, 

 and that a softer steel should have been used. 



Among the remaining papers presented, brief men- 

 tion may be made of a few. Mr. J. A. Ockerson de- 

 scribed a new apparatus for printing conventional 

 topographical signs upon maps by means of a roller. 

 Mr. Clemens Herschel gave a new method of deter- 

 mining the discharge over a submerged weir. Capt. 

 Michaelis read a paper entitled ' Can we make heavy 

 guns?' Professor Egleston added his testimony 

 that there would be no difficulty in making cast- 

 steel guns of a hundred or even a hundred and fifty 

 tons. Mr. C. B. Brush explained the method of 

 aerating the water supplied to Hoboken. The bad 

 taste and disagreeable odor previously existing had 

 been entirely remedied. 



In addition to the reading of papers, some impor- 

 tant business was transacted at the convention . There 

 having been considerable discussion of late in regard 

 to the proj)er relation to each other of the form of 

 the head of a rail, and the flange, and tread of 

 wheels, it was resolved that a committee of five be 

 appointed to investigate this subject. It was also 

 resolved to memorialize congress to appropriate the 

 sum of ten thousand dollars to carry on tests of steel 



