September 19, 1884.] 



SCIENCE. 



289 



cording to the best practice, are given: ninety per 

 cent of the rails must be thirty feet long, and a test 

 piece must be furnished from each charge of steel. 

 These specifications, and the rules by which rails are 

 temporarily or permanently rejected, are elaborate 

 and exact, and must result in a uniformity of quality 

 and composition leaving little to be desired. In track- 

 laying, the rails must meet within r 6 - inch in sum- 

 mer, and -f$ inch in winter. Considerable space is 

 devoted to ties, ballast, switches, frogs, crossings; 

 and attention is called to the importance of the 

 block-system, TYestinghouse air-brake, interlocking 

 switches, etc. 



Mr. Yernon Smith's paper on the Canadian Pacific 

 railway described the construction of the same, and 

 pointed out its advantages. British Columbia joined 

 the confederation in 1871 on a pledge that such a 

 railway should be completed by 1SS1, afterward ex- 

 tended to 1891, seven hundred miles of it to be built 

 by the government. The working season is about 

 five months, and all supplies and men must be brought 

 a great distance. Three gaps, of about four hundred 

 miles each, now remaining, will be completed by next 

 year. No existing railway has been built so quickly : 

 every thing is completed at once, and in the most 

 systematic manner; the longest delay has been one 

 of three hours waiting for material. The road has 

 been run at the rate of three or four miles per day, 

 the maximum day's work being six miles and three- 

 eighths. Different modes of excavating were com- 

 pared; nine thousand Chinese work on the Pacific 

 end; Italians and Swedes excavate twenty-five cubic 

 yards per man per day, with shovels, etc. ; Ameri- 

 cans, with scrapers, move sixty to a hundred yards; 

 and an eight to ten horse grading has been tried. 

 The precaution has been taken of raising the em- 

 bankment to the snow-level. Telegraphic service is 

 established at the same time, which requires an ad- 

 ditional corps of a hundred and fifty men. Coal-beds 

 exist at both ends of the line. Crossing the Rocky 

 Mountains requires some grades of a hundred and 

 sixteen feet to the mile ; but the pass is three thousand 

 feet lower than those farther south, and the rest of the 

 line has easy grades. A degree of longitude on this 

 line is eight miles shorter than on the Union Pacific, 

 so that the route from England to Japan can be 

 shortened a thousand miles. Reference was made to 

 the proposed railway from the Pacific to Hudson's 

 Bay, which would be eighteen hundred miles shorter, 

 but navigation is good only four months yearly, — a 

 great difficulty also with the Canadian Pacific, unless 

 it seeks a new outlet in Nova Scotia. This paper 

 will appear in the transactions in extenso, and will be 

 of great interest in England. Mr. Hannaford re- 

 marked that the six and three-eighths miles per day 

 finished road would, however, be received with an 

 incredulous smile. 



On Friday eight papers were read on Mechanical 

 engineering, and with true courtesy the visiting 

 American engineers were placed at the head of the 

 list: in marked contrast, however, was the want of 

 tact displayed in the reception of Mr. Hoadley's val- 

 uable paper on steam-engineering practice in the 



United States, which was limited to so short a time 

 as to amount to a virtual non-presentation. It is 

 now in book form, and an abstract of the same may 

 be expected at the Philadelphia meeting of the 

 American association. 



Professor Thurston's paper on the theory of the 

 steam-engine was a historical sketch, tracing from 

 the earliest period to the present the progress of the 

 mechanical theory of heat, and the science of thermo- 

 dynamics and its applications, and the completion of 

 the theory by the addition of a theory of avoidable 

 losses. The labors of Rankine and of Clausius were 

 considered as to their influence on the theory of the 

 subject. It was pointed out that Carnot established a 

 number of fundamental principles, and first produced 

 a consistent theory of heat-engines, which was fur- 

 ther perfected by Rankine and Clausius. The lim- 

 itations in applying the thermo-dynamic theory were 

 described, and shown to have been familiar to Watt 

 and to Smeaton, and to have been experimentally 

 examined by Tredgold, Clark, Isherwood, and Hirn, 

 and studied by Cotterill. It was concluded that the 

 history may be divided, as by Hirn, into three peri- 

 ods: 1. Crude theory and incomplete experiment; 

 2. Perfected thermo-dynamics and systematic ex- 

 periment; 3. Complete theory and exact experiment 

 directed toward the determination of wastes. Pro- 

 fessor Thurston calls the last two periods those of the 

 theory of the ideal and of the real steam-engine, and 

 believes that a working theory of heat-engines will 

 soon be completely constructed. The complete pa- 

 per will soon be published. In the discussion it was 

 agreed on all sides, that the thing needed to still 

 further accord theory and practice is an experimental 

 engine specially adapted to scientific investigation; 

 and it is to be hoped that some of our American 

 schools will take hold of the matter before it is done 

 elsewhere. Experiments were also referred to, where 

 a copious supply of oil had reduced cylinder conden- 

 sation in a marked degree. 



Mr. E. D. Leavitt, jun., read a paper on pumping- 

 machinery in America, largely statistical in its nature, 

 in which he briefly sketched the most salient features 

 in the development of the pumping-engine in the 

 United States as applied to water-supply for cities 

 and for mining purposes, giving particulars of the 

 pumping-plant in all the principal water-works in 

 North America. He called attention to the important 

 work done in the development of pumping-machine- 

 ry by the various hydraulic engineers of this Coun- 

 try. Attention was called to those recent improve- 

 ments in pumping-plant which have brought about 

 the present great economy in certain places, most 

 notably those designed by Mr. George H. Corliss, 

 and others by himself. Prominent among these im- 

 provements have been compounding, higher steam 

 pressures, and greater ratios of expansion. In con- 

 clusion, he drew attention to considerations from an 

 economic standpoint, which decide whether to use 

 a cheap plant with no great economy of fuel, or an 

 expensive one from which great economy may be 

 expected; the deciding point being, whether the ex- 

 tra cost of fuel for the cheaper plant will exceed the 



