I am working with a 60 year old schematic and test procedure. The latter refers to adjusting rheostats to "300 DCMI" or "between 100 and 130 DCMI". There are voltage and ammeters attached to different terminals.

The procedure is rather vague, but I'm almost certain that it's referring dc mA. That said, the procedure was probably written by a British firm and I'm wondering if DCMI means something else entirely or if there are subtleties I'm not aware of.

Any help is appreciated. Thanks.