Alexander Mackenzie , PC ( January 28 , 1822 â `` April 17 , 1892 ) was the second Prime Minister of Canada . Alexander Mackenzie , PC ( January 28 , 1822 â `` April 17 , 1892 ) , a building contractor and newspaper editor , was the second Prime Minister of Canada from November 7 , 1873 to October 8 , 1878 .