Mich. Comp. Laws § 290.352
The following test as to quality of galvanizing is hereby declared to be the standard test of the galvanizing of such fence within this state. The wire shall be thoroughly cleansed with a solution of soap, using a soft cloth or cotton waste. It shall then be immersed in a solution of copper sulphate neutralized with copper oxide and filtered, of a density of 1.186 at 65 degrees Fahrenheit. It shall be kept in this solution at a temperature of from 60 to 70 degrees Fahrenheit for 1 minute, then immersed in clear water and afterward wiped dry. After such immersion and drying, if the wire does not show a deposit of copper indicating that some portion of the zinc coating is entirely removed, it shall be considered as "1 minute wire" as hereinafter mentioned. This test shall be immediately repeated and the wire shall be graded according to the number of immersions it may be able to stand without showing a deposit of copper, and such grades shall be designated as "1 minute,""2 minute,""3 minute,""4 minute," etc. wire, in accordance with the number of minutes during which such wire respectively stood such test without showing a deposit of copper: Provided, however, That all tests shall be made on straight sections of stay or line wire and not on locks, wraps or winds of such fence.
MCL 290.352