16S 



KNOVVALEDGE 



[March 1, 1886. 



For M I produced being drawn parallel to I 'G, the angle I B Z will 

 equal angle I' G F, and, as shown above, angle I B Z equals angle 

 I G Z, therefore angle I' (i F equals angle I G Z ; and as, by the 

 above description of the motion of the elliptograph, the whole 

 angle C I G or JI I' G is in any position twice the equal angles I O Z 

 or 1' G F, consequently the angle C I G equals the angle H V G, and 

 therefore the shorter outer arm JI I' being set equal to the shorter 

 inner arm I G will also coincide with the side M I' of the paral- 

 lelogram 11 ]' G I, and its end M with the end of the longer outer 

 arm I JI in any position : and, as shown above, the end M of the 

 arm I JI will describe an ellipse, therefore the end M of the shorter 

 outer nrni M V will also describe a similar and equal ellipse. 



ELECTKIC BURGLAR ALARM. 



[Patent No. 13,525. 1884.]— In this invention by H. C. Eoome, 

 .Tersey City, U.S.A.. each building or structure to be guarded is 

 connected electrically with a differential galvanometer or relay 

 electro-magnet at a central office. The galvanometers or relay- 

 magnets are normally balanced by resistances in the office equiva- 

 lent to those of the external circuits, and should the resistance in 

 any e.xternal circuit be varied by an attempt to open a window or 

 door, A;c., the galvanometer or magnet in the circuit completes the 

 circuit of a relay for raising an alarm in the office. Mechanisms 

 are placed in the office and in the e.xternal circuits and actuated 

 by increasing the current, to introduce corresponding resistances 

 into the external and office circuits at intervals, with the object 

 of preventing any person from obtaining a knowledge of the 

 resistance in circuit. The galvanometers or relay-magnets 

 are cut out of circuit while the resistances are charged to pre- 

 vent a false alarm, due to tlie resistances not being introduced 

 simultaneously into the two circuits, and the battery power for 

 effecting the charge is at the same time introduced by a compound 

 key. One resistance-charged mechanism may be employed at the 

 office to charge the resistance in any number of alarm circuits by 

 replacing it by rheostat resistances after the resistance in any circuit 

 has been charged. When the door, cScc., of any guarded structure is 

 opened, part^f the resistance in its circuit is short circuited, thus 

 giving alarm, and the short circuit is maintained by a short circuit- 

 ing mechanism in the external circuit, even should the door, k.c., be 

 closed again. The short circuiting mechanism may be shunted out 

 of circuit by an electro-magnet excited from the office. Electro- 

 magnetic apparatus is provided for giving alarm when the battery 

 becomes inoperative. This invention is somewhat related in principle 

 to our system of fire-alarms introduced by Sir Charles Bright. It is 

 ingenious and not very complicated, but its adoption would involve 

 the laying or erection of a new system of wires— a serious objection 

 in English towns. 



ORNAMENTING GLASS. 



[Patents Nos. 12,901 and 12,902. 1884.]— The object of the first 

 of these patents, by J. Budd, S. Finchley-road, Surrey, is to impart 

 to sheets of glass the appearance of marble, malachite, onyx, or 

 other stone, for use in the decoration of ceilings, A:c. A tank is 

 partially filled with a mixture of one part by measure of lime with 

 two parts of water, and any ordinary pigments mi.xed with oil and 

 of the tints desired are floated on the mixture. Any other mixture 

 capable of floating the colours may be employed. The glass, 

 prepared or not with gold size or other suitable drying material, is 

 laid on the floating colours, which are thereby transferred to the 

 glass. The veined or ornamented surface is then painted to form 

 the ground, is coated with a mixture of shellac and plaster-of-paris 

 or other backing material, and when dried is ready for use. 



The second patent embraces a device for imparting to glass 

 surfaces the appearance of mosaic work and the like, such as 

 designs upon tiles, &c., chiefly for the decoration of ceilings, kc. 

 The paste obtained by boiling down an aqueous solution of one part 

 strontium nitrate with two parts of ordinary starch is applied both 

 to the glass and to a paper lithograph of the design to be produced. 

 The paper is then laid on the glass and the surplus paste squeezed 

 out. The glass is dried, and the paper is reduced to a \ery thin 

 film by sand-paper or the like, and spermaceti or paraffin wax is 

 applied to form a protective coating and to impart lustre. The glass 

 may also be veined or grained. 



HANGING AND DRAWING CURTAINS. 



[Patent No. 8,8(13. 1884.]— In this invention byJ.Turner,"(!, Hyde 

 Lane, Hyde, Cheshire, the curtains are attached to tapes which 

 are suspended by connecting to eyes cast into the balls sliding in a 

 hollow or grooved pole, the eyes projecting downwards through a 



slot. Cords passing over pulleys through central holes in the balls, 

 and crossing at the centre, are brought down at the side and may 

 be suitably secured. The inner balls are fast to the cord, tlic outer 

 ones to the pole. By pulling either cord, as the case may be, the 

 curtains are drawn or withdrawn. 



LARYNGOSCOPE. 



[Patent No. 10,849. 1884.]— A. H. Vesey, 8, Upper Bedford- 

 place, W.C, has patented this instrument, in which a small incan- 

 descent electric lamp is partially imbedded in some non-conducting 

 material, as cement, contained in a casing which is fixed by a 

 bayonet j(jint within a tube lined with insulating material, to which 

 is attached a German-silver tube of small diameter, containing the 

 wires convej'ing the current. On the silver tube slides a piece car- 

 rying a rod with a mirror at one end, so that the light may be 

 reflected as desired. At the end of the tube is an ebonite handle, 

 containing a switch and resistance coil, so that the strength of cur- 

 rent may be regulated. The connecting wires project from the end 

 of the handle, and are connected to a battery. 



London Institution. — Two lectures were delivered by the 

 Editor of Knowledge at the London Institution on Feb. 18 and 

 Feb. 25, the subjects being "New Stars" and "Volcanoes." 

 There is a greater connection between these stibjects than might 

 at first sight have been supposed. Mr. Proctor showed that new- 

 stars indicate disturbances in our stellar system akin in character 

 to volcanic disturbances in a planet. They are casual or acci- 

 dental phenomena, and do not belong to steady life-processes. 

 He showed that new stars occur in unfinished regions of our 

 galaxy, in star clouds, star clusters, regions of star mist, &c., 

 as is shown by coincidences altogether too numerous and too 

 striking to be accidental. (In passing he presented the thought 

 that the Magellanic Clouds really may be external galaxies— or else 

 outlying parts of our own gala.xy.) In dealing with volcanoes, he 

 showed that they belong to the astronomical at least as much as 

 to the geological aspect of earth-study. He found in the moon 

 evidence of volcanic action such as took place in the past on the 

 earth, the traces having however been removed. He traced comets 

 to volcanic action in terrestrial planets, in giant planets, and in the 

 suns which people space. 



Contents of No. 4. 



PAOK 



The Uultnowatile ; or, the Reli^on 



of Sdenoe. By E. A. Proctor ... 105 

 The Story of Creation : A Plain Ac. 



count of Evolution. By Ed. Clodd. 107 

 Historical Puzzle. By Richard A. 



Proctor 109 



Coal. By W. M. WilUams Ill 



Modern Analytical Chemistry 112 



The Story of the Earth Hi 



Optical Recreations : Colour and 



Light. ByF.R.A.S 115 



Xotes ou Earthquakes. By Richard 



A. Proctor 117 



The Night Skies in Australasia, 



Cape Colony, &c. (///«».) By 



Richard A. Proctor 120 



PiGS 



Indian Myths. By " Stella 



Occidens" 121 



Origin of Comets and Meteors. By 



Richard A. Proctor .'. 12:i 



Bad Times 125 



Geology m London. By W. Jerome 



Harrison I'i^ 



The Migration of Abram 129 



Our Mammal Cousins 12!t 



A Positivist View of the Sermon 



on the Mount 130 



Oossip. By R. A. Procior 131 



New Books to be Read— and Why 13* 



Whist '.. 135 



Chess : An Improved Scale of Odds 



at Chess. By " Mephisto " 135 



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