24 



KNOWLEDGE & SCIENTIFIC NEWS. 



Feb., 1904.] 



19,901. Electric recording apparatus. Hulsmeyer, C. 

 gS, Bilker Allee, Diisseldorf, Germany. Sept. 11. 



record may be used for reproduction by causing it to 

 wise constant beam of light falling on a selenium eel 

 reproducing circuit. 



19,999. Secondary batteries. Fiedler, I, , 

 Street, Tottenham Court Koad, and Puchmu 

 Mornington Crescent, both in London. Sepl 

 Relates to the use of zinc as the ne- 



vary an other- 

 in an electric 



71, Huntley 

 LLKR, c;., 14, 



Relates to apparatus for recording the variations of an electric 

 current in the form of a photographic record produced by the 

 variations in a beam of light. The particular example shown con- 

 sists in imposing sound waves on a microphone n in an electric 

 circuit including a constant battery h and magnet coils il. iP. The 

 armatures of the magnets are mounted on a spring-controlled 

 pivoted mirror c carrying at its centre a mirror /(. A be.am of light 

 k is reflected from the mirror on to a travelling pliotograpliic film 

 ( enclosed in a case having developing and fi.xing apparatus ; 17 is a 

 small opening in the case. The beam of light is varied by passing 

 through an optical plate / of varying transparency from end to end, 

 and is focussed on to the opening ij by one or more prisms or cylin- 

 drical lenses v. The light-varying portions of the apparatus are 

 adjustably mounted to allow of varying the sensitiveness. The 



gative plate. The battery consists of 

 a papier-mache box n containing a 

 tightly-fitting zinc box b, which is 

 connected with a second zinc box (, 

 the two forming one electrode li. 

 Upon the insulating-material, such as 

 asphalt, which covers the bottom of the 

 box /', the lead-peroxide anode 1 stands, 

 and forms the other electrode g. The 

 electrolyte i consists of a mixture of 

 sulphuric acid, mercury sulphate, potas- 

 sium ferro-cyanide, and zinc sulphate, 

 and this forms a covering of zinc - 

 mercury ferro - cyanide upon the zinc 

 electrode, and protects it from the sul- 

 phuric acid when the accumulator is not 

 in use. The electrolyte may be either 

 liquid or rendered " dry " by an ab- 

 sorbent such as sawdust. The cell is 

 closed in with a layer of sawdust /, a 

 piece of cardboaid /; soaked in paraffin, 

 and a layer of mastic material m, through 

 which is an air pipe /. 



FIC I 



LAST YEAR'S WEATHER— FEBRUARY, 1903. 



DISTRIBUTION OF MEAN TEMPERATURE. 



^40 



RAINFALL. 



'? 

 L, 





'J—j- ?n il. 



■J 4.0 f 



'^^ '°'0 'bo? 3° 58 0-99 





0\er the country generally the temperature was considerably 

 above the average, the excess amounting to more than 4 in 

 all districts, exceptinj; the north of Scotland and the south of 

 Ireland, to more than 5^ in many parts of northern, eastern, 

 and central England, and to as many as 0'-*2 at York. 



Rainfall was very deficient in the eastern, central, and 

 southern parts i>f Iinj,;Iand, and also at some stations in the 

 south of Ireland. In the western and northern districts .gen = 

 crally there was a considerable excess, the amount at many of 

 the Scotch stations being more than twice as much as the 

 average. 



