BAIR.D &.TATLOCK (LONDON) LTD. 



5325 



5325 s Resistance Box (Post Office Form) Wheatstone Bridge, comprising set of 17 coils each 

 .1, i, 2, 2, 5, 10, 10, 20, 50, 100, 100, 200, 500, i,ooo, i.ooo, 2,000, and 5,000 ohms, total 

 9,900.1 ohms wound with D.S.C. Manganin wire (non-inductively). The blocks are of 

 heavy brass, 3.5 centimetres long by 19 millimetres wide, and 16 millimetres thick, each 

 brass block has an extra plug hole in centre to fit plug connector terminals, two of which 

 are supplied with box, and are interchangeable with plugs. There are three pairs of 

 proportional coils, two of i, two of 10, and two of 100 ohms. The plugs are all brass 

 with cross pin head, and are accurately fitted into blocks. Two depression keys are 

 fitted and lines marked on top of vulcanite to indicate paths of the wires beneath. Com- 

 plete in mahogany case with hinged cover, adjusted to an accuracy of 0.1 per cent. 



10 15 



5326 



5326 s Kohlrausch Wheel Bridge. In order to obtain the advantage of a long branch wire with- 

 out the inconvenient extension otherwise necessary, the wire in this instrument is wound 

 with 10 turns, about 24 ohms maximum (permanent load about 6 volts), on a slate 

 drum divided into 100 parts on a plated ring mounted on the edge. The moving contact 

 is formed by a small traversing roller, this is also used for counting the turns in circuit, 

 and the permanent connections are made by brush contacts of twenty wires 



5327 s Kohlrausch Wheel Bridge as above, but supplied with comparative resistances of 

 1, 10, 100, 1,000 ohms. 



5 17 6 



800 



CHEMICAL AND SCIENTIFIC APPARATUS AND PURE CHEMICALS. 



969 



