▁Robert son , ▁FR SE ▁▁ 1 9 4 0 - 1 9 4 2 ▁William ▁B ann aty ne ▁▁ 1 9 4 2 - 1 9 4 4 ▁Fin lay ▁James ▁Camer on , ▁FR SE ▁▁ 1 9 4 4 - 1 9 4 6 ▁James ▁Gray ▁K yd , ▁C BE ▁FR SE ▁▁ 1 9 4 6 - 1 9 4 8 ▁Col in ▁Str ath ern ▁P enn , ▁MC ▁▁ 1 9 4 8 - 1 9 5 0 ▁Andrew ▁R uther ford ▁David son , ▁F SS ▁▁ 1 9 5 0 - 1 9 5 2 ▁John ▁Mu ir head ▁Ross , ▁FR SE ▁▁ 1 9 5 2 - 1 9 5 4 ▁Richard ▁Lloyd ▁G w ilt , ▁C BE ▁FR SE ▁▁ 1 9 5 4 - 1 9 5 6 ▁Kenneth ▁Kil pat rick ▁We ather head , ▁MA ▁▁ 1 9 5 6 - 1 9 5 8 ▁Francis ▁Joseph ▁Mc greg or , ▁MA ▁▁ 1 9 5 8 - 1 9 6 0 ▁Alexander ▁Robert ▁Re id , ▁MA ▁▁ 1 9 6 0 - 1 9 6 2 ▁David ▁Al ison ▁Brown ▁Sc rim ge our ▁▁ 1 9 6 2 - 1 9 6 4 ▁Alfred ▁Tre vor ▁Hay nes , ▁C BE ▁▁ 1 9 6 4 - 1 9 6 6 ▁John ▁Les lie ▁Anderson , ▁MA ▁▁ 1 9 6 6 - 1 9 6 8 ▁James ▁B rem ner ▁Dow ,