A superb mechanical engine indicator by Dobbie McInnes of Glasgow - the predecessor to modern engine diagnostics! Such instruments were used to accurately analyse pressure versus piston displacement through the cylinder stroke of an engine, with the output being recorded onto a roll of paper. Dobbie McInnes specialised in these instruments, patenting a number of variations for both steam and diesel engines.
The company ran from Glasgow's Bothwell Street from 1841 onwards and operated under the name of Dobbie McInnes Ltd from 1902 onwards. Most likely this particular instrument dates to the early 1930s, though it has a later service label dated 1956. Case measures 30cm x 22cm x 18cm.
Please read the condition report. Item will be carefully packed and promptly dispatched. Overseas buyers are very welcome but please be aware that import charges may apply.