?????

????????????John Dalton1766-1844????????????????????????????????X???????????????X??????XY?X??????????????XX???????????????????????????????????????????????????????????1798???????????????????????????????8%???0.5%?6%????(?)?2%????(??)???(???)
??????????????????????????????????
???????????????????????????????????????????????????????^?????????????????
????????????????????????????5%8%?0.51%???4%5%?0.5%?8%?0.4%??????5.14%???0.73%??????????
????????
??cone cell??????????????????????????????????????...