Nov. 1 6, 1888.] 



SCIENTIFIC NEWS. 



5i9 



gives utterance, in his usual enthusiastic style, to a somewhat 

 lengthy "Last Word on the Planet Mars.'' In this he care- 

 fully reviews all Schiaparelli's recent observations, and finally 

 comes to the conclusion that " the essential features of the 

 Martian geographical configuration do not change.'' Whilst 

 admitting our knowledge to be as yet insufficient to enable us 

 to theorize, he regards the inundations as due to solar tides, 

 and adheres to the hypothesis that the canals are really 

 rivers, whose straight course is due to the absence of moun- 

 tains (worn down, possibly, by past denudation), and the 

 rapid precipitation of water in an atmosphere whose pres- 

 sure is probably much less than ours. 



Where seas are, there rivers must certainly be, and, as he 

 points out, the canals always open into gulfs of estuarine 

 appearance, and do not actually pass straight across con- 

 tinents, but end usually in lakes, whence other canals emerge, 

 often at an angle. W. S. 



South Kensington, Nov. 10th. 



RECENT INVENTIONS. 



The following list has been compiled especially for the SCIENTIFIC 

 News by Messrs. W. P. Thompson and Boult, Patent Agents, of 

 234, High Holborn, London, W.C ; Newcastle Chambers, Angel 

 Row, Nottingham ; Ducie Buildings, Bank Street, Manchester ; 

 and 6, Lord Street, Liverpool. 



Thermostat, — Messrs. C. R. Kinnell and G. Rothnie 

 have patented a thermostat for automatically regulating 

 the supply of gas or liquid fuel employed in heating 

 buildings. The apparatus is in the form of an ordinary 

 thermometer, having the upper portion of the tube 

 divided into parts through which the gas passes. 

 While the temperature remains below a certain degree 

 the tube is open. If the heat exceeds this degree, then 

 the quicksilver in the thermometer rises and enters this 

 tube, thus diminishing or shutting off the gas supply. 

 The temperature having fallen, the quicksilver falls, and 

 the passage for the supply of fuel is again open. 



Gold Ores. — Mr. P. J. Ogle has patented an arrange- 

 ment of the amalgamated plates used in the treatment of 

 gold ores. The invention consists in employing a series 

 I of short amalgamated copper plates, mounted on a series 

 I of steps furnished with grooves, in which each plate 

 slides, allowing the water carrying the crushed ore to 

 fall from one to the other, thus bringing the float, or fine 

 gold, into actual contact with the amalgamated plates. 

 This arrangement causes the wash water to be broken 

 up, and the plates being adjustable, a fresh surface of 

 mercury can be presented to the wash water as soon as 

 the working surface is inactive through saturation. 



Gases in Mines. — Mr. F. Bosshardt has patented an 

 apparatus for detecting and announcing the presence of 

 explosive gases in mines, on behalf of J. Molas. The 

 apparatus consists in the combination of a diaphragm 

 furnished with silver strips inside a chamber with a 

 suitable number of terminals, in such a manner that on 

 undue accumulation of gases entering the chamber the 

 diaphragm is lifted and forms a contact between the silver 

 strips and the terminals, thus causing a simultaneous and 

 automatic ringing of alarm bells, and the lighting of an in- 

 candescent lamp through suitable electric connections. 



Electric Batteries. — Mr. D. Urquhart has patented 

 a process for the manufacture of elements for electric 

 batteries. The plates or elements are made of peroxide of 

 lead brought into intimate contact by means of an aqueous 

 solution of ammonia, which produces a slow chemical 

 change in the peroxide, causing it to become a 



permanently coherent mass. These plates are then 

 treated with a solution of oxide of lead in caustic 

 alkali. Means for making contact between the elements 

 and the conductors are provided, which consist of an 

 elastic fitting piece pressing platinum foil in contact with 

 the interior of the element, the said platinum foil being 

 connected to the conductors. 



Aluminium.— Mr. A. B. Cunningham has patented a 

 process for producing aluminium and aluminium alloys. 

 A bath of molten lead alloyed with metallic sodium is pro- 

 vided. The aluminium-containing substance is immersed 

 in this bath, and volatilisation takes place, the fumes as 

 they rise being caught and reduced before they can 

 escape. The metal thus obtained having a very low 

 specific gravity and no affinity to lead, rises to the sur- 

 face, whence it may be skimmed off, and afterwards 

 separated from any adhering lead. The process is con- 

 tinuous, as after the removal of the aluminium the bath 

 is replenished with the amount of lead skimmed off, and 

 recharged with sodium. 



Electro-dynamic Generators. — Mr. R. Tathan has 

 patented improvements in electro-dynamic generators 

 and motors. The armature, or equivalent, of such 

 machines is provided with a commutator which rotates in 

 contact with brushes, and the object of the invention is 

 to increase the durability and efficiency of the armature. 

 To carry this out, a to-and-fro motion is given to the 

 brushes, in the direction of the longitudinal axis of the 

 armature. Carriers are provided, and connections 

 whereby the desired motion is imparted to the brushes, 

 and apparatus is provided capable of being thrown into 

 and out of contact with the commutator, for the purpose 

 of truing, polishing, and maintaining the commutator 

 circular in cross section. 



Chromium. — Messrs. T. and E. Rouff have patented a 

 process for the manufacture of chromium, based on the 

 simultaneous employment of alkaline or alkaline 

 earthy chromates, and silica. A neutral chromate is 

 mixed with flint and charcoal, placed in a reducing 

 apparatus and heated to a red heat. At this temperature 

 a silicate and free chromic acid are formed, and the 

 latter is reduced to metallic chromium by the carbon. 

 This spongy chromium is washed to eliminate the 

 silicate, arid a chromium is obtained containing the im- 

 purities of the materials employed. If to the mixture 

 of the neutral chromate, etc., oxides of copper be added, 

 alloys of copper and chromium are obtained in a single 

 operation. 



Power Hammers. — Mr. A. Davy has patented a 

 power hammer which is self-acting and operated by 

 steam. According to this invention the piston is fitted 

 in a cylinder whose lower end is always open to 

 steam pressure, and in which the steam is exhausted 

 from the lower to the upper side of the piston, and 

 thence to the atmosphere, the arrangement of the 

 exhaust ports and the length of the piston being such 

 that one of the ports is always closed by the piston. 

 The length of the piston is about equal to the stroke, 

 and the areas of the upper and lower faces of the piston 

 are so proportioned that the steam, after having passed 

 from the under to the upper end of the cylinder, will, 

 owing to the larger area of the upper surface of the piston, 

 overcome the pressure of the steam on its under side, 



