I believe this is a Phillips Patent oil insulator
made my Bullers and dated 1898 it is a rare beast.
Made by Bullers in 1931
Bennets Patent
...also known in dark brown and there are quite a few
high up on buildings in Dingwall town centre.
Wlii pay £100 for a brown one if anybody has a spare
in good condition?

Telegraph Insulators come in all shapes,sizes, colours and materials.
This one recovered from under a bridge on the Glasgow to Wemyss Bay line
has a groove on the side to carry a telephone line
and a large groove on the top for a power line.
The insulator has been red glazed to warn workers of the risks.
There are no makers marks on this example.
Jobsons Highland Railway Pattern

Used on the line north and west of Dingwall
in the Scottish Highlands 1865

Varley's Patent Insulators were used all over Britain
from 1860 onwards and the No.8 was probable the most common
although they are very hard to find these days.
The '8' refers to the groove/wire size, this being for 8 gauge .