November 5, 1886.] 



SCIENCE. 



413 



should have occiirred to a dejDth fully 100 feet below 

 tide-level, and that, too, directly along the line of 

 the great Appalachian axis, is certainly remarkable. 

 It is further singular, that while the ledges along the 

 shores of the lake are covered with glacial striae, 

 corresponding generally with the course of the de- 

 pression at the point where they occur, the transpor- 

 tation of bowlders has been largely to the north, 

 blocks of fossiliferous limestone from the beds of 

 Mount Wissick being abundantly scattered about the 

 upper end of the lake, but not to the southward. 

 The country between the head of the lake and the 

 St. Lawrence has not yet been examined, but along 

 certain lines is believed to be low. The Madawaska, 

 on the other hand, flowing almost due south, occu- 

 pies a drift-filled valley, bordered by high and steei? 

 hills similar to those of the lake, and probably marks 

 its former extension in this direction. It would seem 

 as if lake and river formed together a great trans- 

 verse channel of erosion, the result of sub-aerial 

 action, from the St. Lawrence to the St. John, at a 

 time when the entire region stood several hundred 

 feet higher than now, and that the movement of the 

 ice was in the direction of the former. The fact that 

 the direct northward extension of this depression is 

 coincident with the famotis gorge of the Saguenay 

 gives additional interest to the observations men- 

 tioned. L. W. Bailey. 

 Fredericton, N.B., Oct. 23. 



Coloring geological maps. 



Professor Branner has issued a neat little card con- 

 taining a colored geological map of the state of Indi- 

 ana, on a scale of 1:4,878,720, or 77 miles to the inch! 

 In a letter, which, from its having been written in 

 French, is probably designed to be widely distrib- 

 uted in Europe as well as this country, he complains, 

 1°, that, with the scale of colors provisionally adopted 

 by the International congress, it is not possible to 

 employ a color which shall indicate the Devonian 

 without specifying whether the area be upper, mid- 

 dle, or lower. Professor Branner will be convinced 

 that he is mistaken if he will look at the report of the 

 committee on the geological majj of Europe (Amer. 

 com. rep., p. 43, 6), where in such a case it was sug- 

 gested (and later approved by the congress) to use 

 the medium shade of color accompanied by the char- 

 acteristic letter of the system (in this case, d), but 

 without any one of the indices 1, 2, or 3 (see Amer. 

 com. rep., p. 103, for the conclusions of the map 

 committee, arrived at after the meeting of the con- 



Professor Branner complains also that the diffi- 

 culty of indicating four or five divisions in the car- 

 boniferous is greater still. This is not surprising on 

 a map-scale of closely one-five-millionth. The con- 

 gress never contemplated such a problem, though 

 even here the individual geologist is expressly left 

 free to employ his ingenuity to differentiate by means 

 of tints and symbols, the only restriction laid upon 

 him being that the base of the tint used shall be 

 gray. This certainly opens the way to any method 

 of differentiation which he may desire to try. 



Professor Branner misunderstands the object of the 

 congress if he supposes that the color-scale was 

 adopted only for the geological map of Europe, and 

 not for the use of all the geologists of the world. The 

 fact is, that the geological map of Europe was simply 

 selected as a lay figure on which to display the pres- 



ent ' provisional system.' If it be found that this 

 system is bad, another will be substituted for it : but 

 it will require more proof than Professor Branner 

 furnishes to convince geologists of this. 



If the ' carbonic ' of Europe can be adequately 

 represented by the proposed system, there is good 

 ground to hope that the carboniferous of Indiana 

 will not present insuiserable difficulty ; but not while 

 the human eye remains what it is can any one suc- 

 ceed in displaying geological details at a scale of one- 

 five-millionth and on a paper surface already one- 

 third covered with printer's ink, representing names 

 of towns and counties and railroad lines. 



It is only fair to add that the system proposed by 

 the congress will come as near to satisfying this im- 

 possible demand as any other. Peesifoe Feazee. 



Air from a cave for house-cooling. 



I wish your opinion upon a matter in which I am 

 much interested. Grand Avenue cave, situated four 

 miles from Mammoth cave, contains some nine miles 

 of avenues filled with delightfully cool, pure, dry 

 air; temperature 55". I propose to erect a house 

 immediately over this cave ; make the outside walls 

 and partitions all hollow, so that they may communi- 

 cate with a cellar, which shall be connected with 

 the cave by a large shaft, say, eight feet square. The 

 question is, will the air between the house and cave 

 take the temperature of the cave by diffusion or 

 otherwise, or will it be necessary to use mechanical 

 means to get the air into the building ? I have seen 

 and spoken to several scientific men on the subject, 

 who agree with me that an interchange of air will 

 take place, and contintie until equilibrium is restored 

 by making the temperatures the same. 



It is proposed to erect a hotel for a cool-air sum- 

 mer resort, and also for a sanitarium. If you think 

 proper, I would like you to put this before the read- 

 ers of your valuable periodical, and get the benefit 

 of their opinions. It is a matter of some scientific 

 interest, in which physicists, geologists, and sani- 

 tarians may be interested. M. H. Oeump. 



Ogden college, Ky., Oct. 26. 



Zinc in Moresnet. 



In your issue of this date, on p. 383, you speak of 

 tin ore being found at Moresnet. This is a mistake. 

 The county contains, however, some of the most im- 

 portant zinc-mines of Europe. Almost every collec- 

 tion of minerals contains some specimens of zinc 

 taken from these very interesting and important 

 mines. Thos. Egleston, 



New York, Oct. 29. 



Ely's Labor movement in America. 



A newspaper discussion in criticism of any partic- 

 ular article or review is rarely profitable, but it seems 

 necessary to make a brief reply to the communica- 

 tion of Professor Ely published in Science for Oct. 

 29. 



Professor Ely charges that his reviewer, while ap- 

 parently neither an untruthful nor malevolent per- 

 son, failed to read the book in question before noti- 

 cing it. Inasmuch as every statement of Professor 

 Ely's which is mentioned in the review is accredited 

 to the page on which it occurs, his allegation is of 



