628 



SCIENCE. 



[Vol. II., No. 40. 



theory, is coatinually flowing in at the sun's polar 

 regions to replace that which, after combustion, is 

 thrown off at the sun's equator. The paper is an 

 important one, but too long to be fairly summarized 

 within our limits. A considerable portion of it is 

 devoted to an endeavor to obviate one of the most 

 serious objections to Siemens's theory of the solar 

 heat; namely, the objection based on the resistance 

 to planetary motions which would result from a 

 cosmical interstellar medium of the necessary den- 

 sity. Werner Siemens argues that the particles of 

 matter passing off from the sun's equator would 

 continue to revolve around the sun as they receded 

 from it, and at any distance would have the same 

 velocity as a planet at that distance, and so would 

 offer no resistance. The paper is, however, mainly 

 occupied with the planetary consequences of solar 

 electrification. — (PMi. mar/., Sept.) c. a. y. [328 



MATHEMATICS. 

 Development of real functions. — The exact 

 title of this paper, by M. J. P. Gram, is ' The devel- 

 opment of real functions in series, by the method of 

 least squares.' M. Gram's pajjer is an exceedingly 

 interesting one, but unfortunately one which can- 

 not be more than briefly referred to in this place, as 

 a suitable notice of it would require the reproduction 

 of a great deal of algebraical vtoA. The principal 

 problem which M. Gram proposes to solve is stated 

 as follows : let there be given a series of arguments, 

 X, and two corresponding series of quantities, Ox and 

 Vx . These last quantities are all real, and, further, the 

 Vx are all positive. Then in a series which contains 

 known functions of x, — viz., yx = Ui Xi + 02 Xj 

 -\- . . . -|- an X,i , — the coeflicients are to be so deter- 

 mined that Sx Vx (ox — Vx )' shall be a minimum. In 

 the first part of the paper, the author gives applica- 

 tions of his process to Fourier's series, spherical 

 harmonics, and cylindrical functions. The second 

 part refers almost entirely to the convergence of cer- 

 tain series ; but without quoting much that is obtained 

 in the first section, and defining many symbols, it 

 would be impossible to give here a suitable or intelli- 

 gible notice of this second section. — (Journ. reine 

 ang. math., xciy. Qi.) t. c. [329 



ENGINEERING. 



Economical pumping-engines. — Mr. C. T. Por- 

 ter reports the duty of the Gaskill engines at Saratoga 

 as 106,000,000 pounds, raised one foot high, per 100 

 pounds of hand-picked coal. The Corliss engines at 

 Pettaconsett, Providence, E.I., gave a duty of 113,- 

 271,000; and the Pawtucket engines have an average, 

 for the year 1SS2, of 113,500,000. The slip of valves 

 is reduced to one-half of one percent. — (Mech., July 

 21.) R. H. T. [330 



Consolidation of bulky materials. — A steam- 

 hammer has recently been applied to the consolida- 

 tion of bulky materials in steel moulds. The mate- 

 rials are usually organic, often fibrous, and one blow 

 generally does the work. Four blocks per minute 

 are made; 3,000 pounds of sawdust are compacted 

 into blocks each hour. Bran is thus made denser 



than flour, and can be preserved indefinitely. Stone 

 is made from earth or sand, and weighing lliO pounds 

 per cubic foot. The following are results so ob- 

 tained : — 



— {Iiidustr. world, 3\ine.) k. n. t. [331 



Economy of steam-boilers. — William Kent re- 

 ports, to the American society of mechanical engi- 

 neers, the results of a series of tests of fuels in various 

 ways, and under various forms of boilers. He gives 

 the following as reliitive values of fuels determined 

 by burning under the Babcock & Wilcox boilers : — 



Welsh bitum 109.0. 



Scotch bitum 109.5. 



Cambria, Penn., semi-bitum. . . . 91.2. 



Pittsburgh, Penn., bitum 99..5. 



Ohio bitum S4.9. 



Vancouver's Island 85.7. 



The paper is long and unusually complete. — {Ibid.) 

 E. H. T. [332 



METALLURGY. 

 Bessemerizing copper mattes. — Pierre Jlanhds 

 claims to have overcome all the difficulties in Bes- 

 semerizing copper matte, and to have charge of an 

 establishment which is, at the present time, success- 

 fully making copper on a commercial scale. He 

 melts the ore in a suitable cupola furnace, casting 

 the matte produced into a Manh^s converter, when, 

 under the action of a high-pressure blast, it is rap- 

 idly transformed into 98 % to 99 % black copper. The 

 Manilas works consist of three cupolas of twenty- 

 five to thirty tons' capacity per day; two small cupo- 

 las for remelting the matte in case of neeil; three 

 Manhes converters, treating a ton and a half of 

 matte at each operation, and each converter makes 

 twenty-two to Iwenty-fouroperationsperday; and the 

 necessary hlowing-engines. Manhes claims that cost 

 of labor is reduced to a minimum, becausfe operations 

 last only a few minutes, and large quantities of metal 

 are handled. The cost of fuel is low; because no 

 fuel is needed to bring the matte forward to black 

 copper, except that used for the blowing-engine. 

 The saving in cost over the Welsh or Swansea pro- 

 cess, according to local conditions, is from .10 % to 

 75%. — (Eng. min. journ., Jane :iO.) k. 11. k. [333 



AGEICULTURE. 



Seed-testing. — Comparisons between the ger- 

 minating and vegetating powers of seeds, made at 

 the New- York agricultural experiment-station, show 

 that the two are by no means identical. Many seeds 

 which were capable of putting forth a radicle failed 



