![](https://coimages.sciencemuseumgroup.org.uk/425/877/large_thumbnail_1994_8783__0010_.jpg)
Telegraph block instrument (receiving)
![Telegraph block instrument (receiving)](https://coimages.sciencemuseumgroup.org.uk/534/206/medium_smg00358074.jpg)
Telgraph block instrument; MR. Rotary non-pegging/routeing 1-needle absolute 3-position/indication, with wood routeing-handle and one brass-plated ("Line Clear Cancel") bakelite push-button. Dated 1899; Maker: Brittan, London.