"made to its principal" changed to "made its principal"
"american manner" changed to "American manner"
Page 35: "many tenths of a year" changed to "many tens of years"
Page 38: "same appearence" changed to "same appearance"
Page 47: "red stears" changed to "red stars"
"dispersion in M" changed to "dispersion in M"
Page 49: "smaller the" changed to "smaller than"