![](https://coimages.sciencemuseumgroup.org.uk/5/924/large_thumbnail_1930_0422__0001_.jpg)
Model to illustrate the principle of reciprocity.
![Model to illustrate the principle of reciprocity.](https://coimages.sciencemuseumgroup.org.uk/371/665/small_thumbnail_smg00061808.jpg)
![Model to illustrate the principle of reciprocity.](https://coimages.sciencemuseumgroup.org.uk/53/376/small_thumbnail_1930_0451__0001_.jpg)
![Model to illustrate the principle of reciprocity.](https://coimages.sciencemuseumgroup.org.uk/53/377/small_thumbnail_1930_0451__0002_.jpg)
Model to illustrate the principle of reciprocity.
Many objects in Lord Rayleigh’s collection are annotated with a reference to the volume and page of his collected works where they are discussed.
Object 1930-451 is inscribed with pencil “V p 170”. (Difficult to read, and especially the “0” is uncertain.