I did a little more digging. The Montreal city directories are online at
http://bibnum2.banq.qc.ca/bna/lovell/It looks like they were dealing in Telephone and Electrical supplies from about 1889 to 1907.
Ness and Co first shows up in the 1885 -1886 Montreal Directory as Ness and Co, Carlington, Eng. Manufacturers of Thymo-cresol, F.J Prior, sole agent. 759 Craig.
In 1889 - 1890 They are listed as Ness T.W. Dealer in Dodge Wood Split Pulleys, Electrical Supplies, Typewriters, Cash Registers, Copy-graphs and office Specialities 694 Craig, Branch 368 St. James.
In 1890 - 1891 They show up as Ness T.W. Canadian headquarters for Electrical Supplies, and dealer in Dodge Wood Split pulleys. 644 Craig, h (home) 205 Versailles
In 1891 - 1892 They drop everything else and speicalize in Telephones and electrical supplies: Ness T.W., Manufactuere of: Telephones, Annunciators, Electric bells, etc. The CANADIAN HEADQUARTERS for ELECTRICAL SUPPLIES of every description. Tel.: Bell 1100; Fed. 584. 644 Craig St. house 678 Sherbrooke st. (Note they got a phone! actually 2 as there were 2 different competing telephone systems in Montreal at this time and they wanted to service customers on both systems)
1895 - 1896 was the first year they show up as Ness, McLaren and Bate: Manufacturers of Telephones, Annunciators, Electric Bells and Electric Light Supplies, 749 Craig St. T.W. Ness' residence is listed as 211 Mance
In 1898 - 1899 they change address: Ness, McLaren and Bate, Mfrs. of Telephones and Electrical Supplies, Contractors for Electrical Light Wiring, Etc., Bell Tel. Main 1100, Merchants 674. 419 St. James St., Corner Craig
In 1903 - 1904 They change addresses again: Ness, McLaren and Bate Telephones, Telegraph Instruments, Annunciators, Bells, Batteries, & c. Electric Light and Bell Wiring. Repairs a speciality 732 Dorchester, cor Bleury. Long Distance Tel Main 1100
The location looks the same in 1906 but the address changes to 230 Dorchester st. West, cor. Bleury.
In 1908 - 1909 they are no longer listed, but at the same address there is listed the Canada Electric Co (230 Dorchester West) - Canada Electric Co, Lacasse Rousseu, Mngr. Mnfrs, and dealers in Electric Fixtures and Electric Supplies. Office and Factory 230 Dorchester West. Bell. Tel. 722