Nov. 9, 1888.] 



SCIENTIFIC NEWS. 



495 



improvement in the construction of the cores of arma- 

 tures of electro motors and dynamo machines. It con- 

 sists in the employment of collars, keyed to an armature 

 spindle. One of these collars is capable of longitudinal 

 movement thereon, while both collars are formed with 

 grooves the bottoms of which are inclined. These 

 grooves receive keys having correspondingly inclined 

 surfaces, so that the longitudinal movement of one of the 

 collars will cause the keys to move outwards, and by 

 acting upon the plates or wire of which the armature is 

 built up, will firmly hold and tighten same, while exerting 

 a yielding or elastic pressure thereon. 



Firearms. — Mr. H. S. Maxim has patented means 

 for pointing fire-arms. The object is to enable a gun to 

 be elevated and sighted accurately without previously 

 ascertaining the distance between the gun and the object 

 aimed at. It is based upon the fact that the greater the 

 distance of an object from a given point the less will be 

 the angle at this point subtended by the object. It is 

 carried into practice by providing a sight of two pieces 

 arranged so as to be simultaneously adjusted toward or 

 from each other, that is to say, assuming these adjustable 

 pieces to be arranged in the back sight, the said pieces 

 will be moved towards each other simultaneously with 

 the raising of the sight and away from each other by the 

 lowering thereof. The fore-sight is formed with a hole 

 and two pins extending horizontally from opposite sides 

 of the eye to its centre. 



Mariner's Compass. — Mr. J. C. Dobbic, of Glasgow, 

 has patented improvements relating to the mariner's 

 compass, comprising means for the suspension of the 

 compass bowl and for the taking of azimuth bearings. The 

 bowl of the compass is suspended by means of a link or 

 chain from a metallic spring fastened vertically to the 

 interior of the binnacle casing, or the springs may be 

 horizontal and the gimbal ring provided with bearings 

 which fit in or upon sockets formed on the before-men- 

 tioned springs. For taking azimuth bearings, a reflecting 

 mirror is fixed on the case. This mirror is formed of 

 two parts, hinged, or otherwise adjustable, so that one 

 serves to reflect the object whose bearing is to be taken, 

 and the other the reading of the compass-card. In use 

 the mirrors are adjusted by hand to the requisite posi- 

 tion, and the reading of the card is facilitated by the two 

 mirrors. 



Galvanometers. — Messrs. W. E. Ayrton and J. Perry 

 have patented a galvanometer. The invention relates to 

 galvanometers of the siphon recorder type, whether used 

 as measuring instruments or as telegraphic receivers. In 

 order to prevent the sensibility of the instrument being 

 altered by either a temporary or permanent variation of 

 the strength of the magnetic field in which the movable 

 coil is suspended, one or more small permanent magnets 

 are attached to the movable coil with their magnetic 

 axes parallel to the plane of the latter ; the moment of 

 the controlling couple and that of the deflecting couple 

 then alter in the same ratio with any alteration in the 

 strength of the field. When the zero is altered, for ex- 

 ample, by bringing the instrument near a dynamo, the 

 magnet or coils which produce the magneticfield are turned 

 about an axis, passing through the axis of suspension of 

 the movable coil into the proper position. The connec- 

 tions with the suspended coil may be made by means of 

 mercury cups, or preferably by fine wire spirals. 



ANNOUNCEMENTS. 



Cambridge. — At St. John's College the following scholar- 

 ships and open exhibitions are offered for competition to 

 persons not yet in residence : — 1. Foundation scholarships, 

 two of the annual value of ^80, two of ££>o, and two of £s°> 

 tenable for two years, and the tenure may be prolonged for 

 two years more. 2. Minor scholarships, four of the annual 

 value of £50 tenable for two years, or until the holder is 

 elected to a foundation scholarship. 3. Exhibitions varying 

 in number and value according to the merits of the candi- 

 dates and the number of vacancies at the time of the election. 

 Candidates for scholarships must be under nineteen years of 

 age, but this res'riction does not apply to candidates for ex- 

 hibitions. Besides scholars and exhibitioners, a certain 

 number of sizars may be elected according with the results 

 of the examination. Candidates may present themselves 

 for examination in classics, mathematics, natural sciences, 

 Hebrew, and Sanskrit. The examination in classics and 

 natural science will commence on Tuesday, December nth; 

 in mathematics and Hebrew on Thursday, December 13th. 

 Candidates in Sanskrit must give a month's notice of their 

 intention to present themselves for examination. The name 

 of every candidate with certificate of birth and character 

 should be sent not later than December 1st to the tutor under 

 whom it is proposed to place him. Names will be received 

 by any one of the tutors, Dr. Sandys, Rev. E. Hill, Mr. W. E. 

 Heitland, and Rev. J. T. Ward. 



London Institution. — The following lectures will be 

 delivered on Mondays and Thursdays, commencing Nov. 

 19th : — " Time and Tide — the Romance of Modern Science," 

 Sir R. S. Ball, F.R.S. ; " Electrical Transmission of Power," 

 Prof. W. E. Ayrton, F.R.S. ; "Time and Tide — the Romance 

 of Modern Science," Sir R. S. Ball, F.R.S. ; " Handel— Vocal, 

 Instrumental, and Pictorial Illustrations," William H. Cum- 

 mings, Esq. ; " The Colours of Polarised Light," Prof. Thomp- 

 son, D.Sc, BA. ; " Political Progress in the Seventeenth Cen- 

 tury," Prof. Samuel Rawson Gardiner, LL.D. ; " The Colours 

 01 Polarised Light — Part II.," Prof. Sylvanus Thompson, 

 D.Sc, B.A. ; " Life History of Some Plants," Prof. Charles 

 Stewart; "The New Forces in India," Sir W. Wilson 

 Hunter, K.C.S.I., C.I.E., LL.D. ; " Life History of Some Ani- 

 mals," Prof. Charles Stewart ; "The Story of a Tinder Box," 

 with Experiments (Christmas Course for Juveniles), Dr. 

 Meymott Tidy, F.C.S. ; " Art and Artists," with illustrations, 

 Harry Furniss, Esq. ; " Pigmies," Prof. Flower, C.B., LL.D., 

 F.R.S.; "Recent Babylonian Explorations," W. St. Chad 

 Boscawen, Esq. ; " The English Novel in the Seventeenth 

 Century," Edmund Gosse, Esq., MA. ; "Astronomical Pho- 

 tography," A. A. Common, Esq., F.R.S. ; "The Times of the 

 Twelve Caesars," Rev. Canon Benham, B.D. ;" "Modern 

 Wit," Armytage Bakewell, Esq. ; " The Times of the Twelve 

 Apostles," Rev. Canon Benham, B.D. ; " Caedmon — Our First 

 Poet in the Island of England," Rev. Stopford Brooke, M.A. ; 

 "Men, Women, and Artists," Harry Ouilter, Esq., M.A. ; 

 " Some Curiosities of Magnetism," Shelford Bidewell, Esq. ; 

 " Darwin versus Lamarck," Prof. Ray Lankester, F.R.S. ; 

 " Ants," Rev. J. G. Wood ; "The Legend of Beauty, or, Art 

 as Representing the Passion of our Lives," Wyke Bayliss, Esq., 

 F.S.A. ; "Recent Studies of Some Forms of Minutest Life," 

 Rev. Dr. Dallinger, F.R.S. ; " Modern Composers of Classi- 

 cal Song — I. Franz Liszt, Johannes Brahms, and others," 

 Carl Armbruster, Esq.: "Soap Bubbles, and what maybe 

 shown with them," C. V. Boys, Esq. ; " Modern Composers 

 of Classical Song — II. Robert Franz," Carl Armbruster, Esq. ; 

 " Marriage Laws — Ancient and Modern," E. B. Tylor, Esq., 

 D.C.L., F.R.S. ; "Algeria and Morocco," Henry Blackburn, 

 Esq. ; ' Our Early British Ancestors," Prof. W. Boyd Daw- 

 kins, F.R.S. ; " The Phonograph," Col. Gouraud ; " The Cha- 

 racters of the Great Composers, and the Characteristics of 

 their Works," Prof. Ernst Pauer. The Christmas Course, by 

 Dr. Meymott Tidy, is intended for juveniles, for whom seats 

 will be specially reserved. Further particulars can be ob- 

 tained on application to the Secretary of the London Institu- 

 tion, Finsbury Square, E.C. 



