William Irvine was consecrated a
college bishop
In the early days of the Scottish Episcopal Church, college bishops were men who were consecrated bishops in order to maintain apostolic succession but (extraordinarily) not appointed to any episcopal see
An episcopal see is, in a practical u ...
(i.e., a bishop without a diocese), on 22 October 1718.
["History of the Scottish Episcopal Church: From the Revolution to the Present Time" Lawson, J.P p530 : Gallie & Bayley, 1843]
References
College bishops
{{Anglican-bishop-stub