XI. APPLICATIONS. 3 1 3 



f. Varley's Lightning Protector (original form). 

 



* )> 5> 



k. Varley's vacuum (modern form). Tube 



/. protector, vacuum tubes in water-tight 



i. ,, compartment for outdoor use. 



7i. Latest form of fine wire protector, Post 



Office pattern, consisting of a metallic bobbin, electro-nickel plated, in con- 

 nexion with the earth. It is wound with a fine wire covered with silk and passed 

 through melted paraffine wax, the wire being placed in the line circuit. The 

 metallic bobbin is carefully lacquered to secure insulation in damp situations. 



1576. Insulators. Various. 



Original ring insulator. 

 Cone insulator, original form (1845). 

 later 



form for repairing broken insulators. 



Walker's double-cone insulator (brown). 



(white). 



Insulator (1847), in which the bolt by which the wire is suspended is in- 

 sulated by mastic cement in the cavity at the top of the insulator. 

 Brown earthenware insulator, with zinc cap (1850"). 

 Do., with groove for wire. 

 Do., glass instead of earthenware. 

 (1851) brown earthenware. 



glass. 



Clark's invert insulator, corrugated. 

 Varley's double-cup insulator, fitted. 

 Ditto, in separate parts, 1862. 

 Varley's No. 1 1 wire double-cup insulator. 

 Brown earthenware insulator called (Z). 

 Jobson's invert white, double shed. 



single. 



South Devon invert insulator (brown). 



(white). 



Andrews' invert with ebonite inner shed. 



bolt tube 



bolt tube and shed. 



Ebonite insulator, single shed. 

 Old form of shackle. 

 Bright' s shackle. 

 Modern terminal insulator. 



1576aa. Telegraph Apparatus, &c. 



General Direction of Russian Telegraphs. 



1. Atlas, containing details of the construction of the Central Telegraphic 

 Office in St. Petersburg. 



2. Lightning conductor, for cable. 



3. Lightning conductor, for station. 



4. Insulator, with double cup (large model), " KornilofFs." 



5. Insulator, with double cup (small model), same make. 



6. Insulator, with double cup (large model), " Belotine's." 



7. Insulator, with double cup (small model), same make. 



8. An element, " Meidinzer's." 



1576a. Wheatstone Kaleidophone. 



The British Telegraph Manufactory, Limited. 



