310 



SCIENCE. 



[N. S. Vol. V. No. 112. 



the investigation of glacial phenomena both 

 present and past. In connection with the latter 

 especial attention should be paid to evidences 

 of glaciation on the highest peaks and to the 

 outermost points of land. Also attention should 

 be paid to evidences of past subsidence or ele- 

 vation of the coast. Other branches of science, 

 however, should not be ignored. The make-up 

 of each party should be about as follows : a 

 glacialist, as director in charge ; a general geolo- 

 gist ; a zoologist ; a botanist ; a meteorologist 

 and an ethnologist. If possible, a physician 

 should be obtained for each party, who could 

 also act in one of the above capacities. So far 

 as possible each member of a party should be a 

 trained observer. In an expedition of this kind 

 there should be no members that are not enthu- 

 siastic in the work, and each should be prepared 

 to make the best of the opportunities offered in 

 the necessarily limited time. The necessary 

 expense, considering the circumstances, is not 

 large, and it ought to be possible for each party 

 to have sufiicient funds to allow the director to 

 select the other members. 



Finally, although one summer's observations 

 would amply repay the time spent and ex- 

 pense incurred, provision could be made to 

 secure greater results through each party ar- 

 ranging to have its observations carried on by 

 parties in succeeding seasons. It seems pos- 

 sible now that Greenland may be visited nearly 

 every year by expeditions from the United 

 States; certainly the six Peary expeditions 

 have shown this to be practicable. In such 

 case the return of a single member of a party 

 to the position of the preceding year would 

 enable a valuable series of observations to be 

 made upon the edge of the inland ice and upon 

 the motion of the glaciers by means of datum 

 points established by the parties. Such datum 

 points could be so located as to be found and 

 used by one not a member of the original 

 party. 



The writer hopes to return himself to 

 Greenland during the coming summer and 

 continue the observations begun by the Boston 

 party last summer. 



A word may be necessary to call attention to 

 the summer climate of Greenland. For camp- 

 ing during that season there is no serious ex- 



posure involved. The very long days with the 

 sun above or only slightly below the horizon 

 for the full twenty-four hours prevents the 

 temperature ever becoming very low, and the 

 continual daylight affords facilities for work or 

 travel at all hours. 



During the last summer the Boston party en- 

 countered no serious cold, the lowest recorded 

 with a minimum thermometer being 26° above 

 zero, F. As far as climate is concerned there is 

 no reason why Greenland should not be a 

 pleasant resort for the summer. 



Geo. H. Barton. 



Massachusetts Institute op 



Technology, Boston, Mass. 



coloe-blindness and william pole : a study 



IN LOGIC. 



It has long been matter of common knowl- 

 edge among psychologists that the color-sensa- 

 tions which persist, in the ordinary cases of 

 partial color-blindness, are blue and yellow. 

 This was a requisite consequence of Hering'a 

 theory and was predicted by him; it vias proved 

 by the first case of monocular color-blindness 

 which was observed — that of v. Hippel in 1880 

 — and this proof has been abundantly confirmed 

 by the cases which have been discovered since. 

 But the theory of Young and Helmholtz ap- 

 parently required that, when two color-sensa- 

 tions only persisted, if one was blue the other 

 must be either red or green. Now, the physi- 

 cists (and most physiologists as well) too hastily 

 took the Young-Helmholtz view as expressing 

 fact and not theory, and they continued to infer 

 (although Helmholtz himself had recognized 

 the true state of the case) from the circum- 

 stance that the partially color-blind had two 

 sensations only, that these sensations were, in 

 the ordinary cases, blue and red, or blue and 

 green ; and in accordance with this deduction 

 they classified most cases of color-blindness as 

 red-blindness or green-blindness (without ex- 

 pressly stating that, in their view, in both 

 cases, blindness to yellow was involved as 

 well). There was absolutely no reason except 

 the theory for affirming that the warm color of 

 the defective person was either red or green ; 

 all that was known was that it occupied that 

 portion of the spectrum which, for the normal 



