September 11, 1885.] 



SCIENCE. 



215 



the secretary. The abstract enumerated the advan- 

 tages of the arrangement of multiple radial cylinders, 

 the pistons of which act upon the inside of a vibrat- 

 ing eccentric. In the discussion, several novel forms 

 of this kind of motor were recalled, as having been 

 used or tried ; but it was shown, that thus far the 

 advantages claimed had not usually been sufficient 

 to counteract the objection of complicated construc- 

 tion. Being best adapted for slow speeds, these mo- 

 tors are not economical for steam on account of 

 excessive cylinder condensation. 



The subject of the next paper, by Mr. Stephen S. 

 Haight, was the use and value of accurate standards 

 for surveyors' chains. The chain described was of 

 flattened steel-wire, with thermometer attached to 

 record temperature, a spring-balance to weigh the 

 tension under which the chain is used, and a spirit- 

 level. Professor Davis exhibited a tape, such as his 

 experience had proved to be practical for ordinary 

 work, and which, though not capable of so great 

 accuracy, perhaps, as the one described by Mr. 

 Haight, he had found amply so for general use in a 

 large range of work in the state of Michigan. Pro- 

 fessor Davis also exhibited a reel of simple construc- 

 tion. The president read some notes from Prof. W. 

 A. Kogers, chairman of a committee on standards of 

 measurement. These notes contained one suggestion 

 relating to greater precision in the use of calipers. 

 As shops are coming more into the practice of having 

 tool-rooms. Professor Kogers proposes to have a com- 

 parator in the tool-room of each shop, and to have 

 the calipers sent to this room to be nicely set to exact 

 size, thus eliminating the errors so sure to exist 

 under the ordinary methods. The fact, that some 

 metals and alloys when subjected to change of tem- 

 perature do not return to their original volume when 

 the normal temperature is restored, was mentioned 

 as a possible cause of variation in standard measures, 

 and fault of adjustment in instruments of precision 

 made of such metals. Iron does not show this prop- 

 erty of a ' set ' in the ordinary range of temperature 

 within which such instruments are used. The com- 

 mittee on accurate standards was continued for 

 another year. 



A short paper by Prof. J. B. Webb, on the lathe as 

 an instrument of precision, called attenion to the 

 lack in most lathes of that exactness of construction 

 required to give a lathe the 'fine sense' of precision 

 which some instruments possess, so that it is usually 

 a machine for the economic removal of metal, rather 

 than for the production of exact forms. There is at 

 present no uniform method or available apparatus 

 by which a purchaser may test the degree of error in 

 any given lathe. Some simple methods for making 

 such tests were briefly described. Another paper by 

 the same author, on the economy of accurate stand- 

 ards, set forth the increased money-value of such 

 articles as machine-bolts, screws, etc., when nicely 

 fitted by accurate standards. 



A paper by Mr. C. J. H. Woodbury, on the co- 

 eflBcient of efilux of automatic sprinklers, described 

 these sprinklers, which are devices for extinguishing 

 fires. The sprinklers are attached to pipes, and the 



water is automatically let on to the sprinklers by the 

 melting of solder under the action of heat caused by 

 the fire. It often happens that the pipes conveying 

 the water to the sprinklers are too small to deliver the 

 required volume of water. The paper gave the re- 

 sults of the author's experiments for determining 

 the coefficient of efflux, and the formula for discharge 

 of automatic sprinklers attached to commercial fit- 

 tings; also the means of determining the number of 

 sprinklers on given pipes, which will make the losses 

 due to friction approximately equal, and not so great 

 as to impair the efficiency of the apparatus. In the 

 discussion, various methods of preventing the freez- 

 ing of the water in winter were described, a simple 

 one being to fill the exposed pipes with compressed 

 air. This involves careful fitting of joints and valve- 

 stems. This has been done so successfully as to 

 show a loss of only two pounds' pressure per week 

 from leakage. Where an air-tight tank is used, the 

 compressed air may fill the space above the water in 

 the tank as well as the exposed pipes. In this case, 

 there need be no valve or mechanism between the 

 tank and the sprinkler; and when the passage to the 

 sprinkler is automatically opened, the air in the pipe 

 first rushes out, followed by the water which is forced 

 out by the pressure of the air in the tank. 



Mr. Frank C. Wagner presented an elaborate paper 

 on electric-light tests, giving an account of his work 

 in testing the efficiency of two electric-light plants. 



Prof. M. E. Cooley explained and illustrated a method 

 of testing indicator-springs. The method consists in 

 placing a small rigid rod in a vertical position, with 

 its lower end resting upon a standard-scale. Upon 

 the upper end of the rod, the under side of the piston 

 of the indicator rests. The indicator is fastened to a 

 horizontal bar movable on vertical guides. When this 

 bar is pressed down by means of thumb-screws upon 

 the guide-rods, the pressure on the piston, and, con- 

 sequently, on the spring of the indicator, can be 

 weighed upon the scales, and the position of the 

 pencil recorded by a mark upon the card. Experi- 

 ments made when the spring was heated nearly to 

 212°, showed that the resistance of a sixty-pound 

 spring was diminished about one pound by change of 

 temperature. Professor Cooley also explained a new 

 smoke-burning device, consisting of a rectangular 

 slot through each door of the furnace, just above the 

 level of the hot coals, and two three-eighths of an inch 

 steam-pipes entering the furnace above the doors, 

 and so directed that a jet of steam passing through 

 them strikes the fire about two feet back of the door. 

 As the air passes in through the slots, and over the 

 live coals, it becomes heated; and when it meets the 

 steam-jets, is thoroughly mixed with the products of 

 combustion, and completely oxidizes them. The only 

 condition requiring careful attention is that live 

 coals shall be kept at the front of the furnace, and 

 nearly on a level with the slots in the doors. 



In a paper entitled *Deep water at Galveston, 

 Tex., and how to secure it,' Dr. Alexander Hogg 

 advocated the construction of a break-water ex- 

 tending out two miles from the shore as the best 

 solution of the problem. From the discussion, it 



