132 



SCIENCE. 



[Vol. X. No. 240 



recognition. Physiography now is in the low position that natural 

 history occupied in the first half of the century, when its text- 

 books gave brief descriptions and pretty little wood-cuts of a great 

 variety of forms, dwelling on their slight differences more than on 

 their great resemblances. In a score or more of years, physiog- 

 raphy will be fortunate if it attain as high a position as is now 

 held by biology, the successor of the old natural history, in 

 which a few forms are first studied minutely, and the knowledge of 

 detail thus gained is broadened by giving emphasis to the resem- 

 blances that relate these few types to all the rest of the animal 

 and vegetable world. As far as the economic relations of plants 

 and animals to liuman history are concerned, some might be con- 

 tent with such a statement as ' a horse is a horse;' but the study of 

 zoology for itself, without regard to its relations to history, must 

 regard a horse as a highly specialized form of a general type, and 

 must discover how his specialization was accomplished. 



Physiography must make the same advance. It might serve the 

 needs of physical geography if physiography made no distinction 

 between a new plain smoothed by constructive process and an old 

 base-level plain smoothed by destructive process ; but to physiog- 

 raphy itself the omission of this vital distinction is absolutely fatal. 

 Placing such apparently similar forms together would involve the 

 same order of error as that of classing whales with fishes, or of 

 grouping the unwrapped cephalopods of the mesozoic with the 

 straight forms of the low paleozoic. Time must be recognized as 

 an element in geographic description even to a greater degree 

 than it has been by Prof. Archibald Geikie in his study of ' geo- 

 grapic evolution ; ' for topographic development is the key to a 

 real understanding of the forms of the land about us. Physiog- 

 raphy must, moreover, follow the example of biology in studying 

 its simpler type-forms carefully before attempting to understand 

 the complex associations of forms that make up a country or a 

 continent. 



Continental homologies have gone far enough already, if indeed 

 not too far, in the present state of knowledge : attention should be 

 directed instead to the minute morphology and systematic develop- 

 ment of individual topographic forms. The difficulties of such work 

 are great, especially in teaching ; for while it is admitted that ' seeing 

 is believing,' and methods of instruction in chemistry, physics, and 

 organic natural histoiy are all remodelled with this principle in 

 view, geography can at best secure but an imperfect application of 

 the principle, and has to get along with maps, views, and models, 

 instead of studying actual forms themselves. Maps are nearly al- 

 ways on too small a scale, and too poorly drawn to show what 

 ought to be seen. Photographs are of course extremely useful, but 

 they generally inr'i'.dc loo many varieties of form, and present too 

 much detaii, to serve best in elementary instruction ; and they are 

 a.£ a rule taken with a geographic rather than a physiographic object. 

 Illustrations in books of travel are too often of no scientific value : 

 the traveller is generally an explorer instead of a geographer, and 

 the artist too often stays at home. Most of Holzel's oleographs are 

 admirably artistic, and all are highly valuable, and they probably 

 come as near to being ' types ' as any thing published. The illustra- 

 tions in the reports of our Geological Survey are also most excellent 

 in this respect. Models are too often merely copies of actual places 

 that have been, for such a reason as complexity of structure or the 

 like, chosen for this kind of illustration : the model of Monte Rosa 

 mentioned by Mr. Keltic, excellent as it must be as the work of 

 so artistic a geologist as Professor Helm, and so appreciative a 

 topographer as Herr Imfeld, must have about the same relation to 

 the needs of a class in physiography as a menagerie would have to 

 the needs of a class in biology, or as Leverrier's computations about 

 Neptune would have to a class in mathematics. Mr. Keltic recog- 

 nizes, however, that, for teaching purposes, " it should be remem- 

 bered that it is not extraordinary features that are desired, but 

 typical aspects of the earth's surface," but he does not say where 

 we shall find a scientific and sufficient investigation of the forms 

 that are to be chosen as ' typical aspects.' There is no such investi- 

 gation. The absence of any thorough and consistent physiographic 

 terminology at once points out the immaturity of this study. Be- 

 ginnings may be found here and there, but certainly not in ' numer- 

 ous text-books.' The Sixth Annual Report of the Geological Sur- 

 vey, just issued, contains, for example, a number of illustrations 



that will be seized upon when the proper text-book appears. The 

 choice little woodcuts on page 229, entitled ' Topographic Old Age,' 

 and ' Topographic Youth,' are particularly good, but these terms 

 will certainly be new to most readers. 



Let me repeat, therefore, that while the principles of physiography 

 are coming to be pretty well understood, the facts have yet to be 

 set forth in their proper light, and the world must be explored 

 over again to find them. Let any one who doubts this read over 

 the ordinary books of travel and the older geological and geographi- 

 cal reports, and see what sort of a physiography he can make out 

 of them. Before the methods of teaching physiography are per- 

 fected, before the proper illustrations are constructed, much discus- 

 sion is needed as to the principles to be taught, and as to the forms 

 that are to be chosen for types. The Geographical Society still has 

 a large work before it in this direction. W. M. Davis. 



Cambridge, Mass., Aug. 28. 



The Blair Educational Bill. 



In Science of Aug. 19 is a note on the Blair bill, by James Law- 

 rey of Iowa. Mr. Lawrey declares that " any State that would ac- 

 cept national aid has not the spirit necessary to a sound govern- 

 ment." Such a statement comes with very poor grace from one 

 who resides in a State in which the schools are most richly en- 

 dowed by the general government. Whence came the great educa- 

 tional funds of the western States, save from the munificent bounty 

 of the general government ? Has the spirit of the people of the 

 State of Iowa, or of any western State, been, in any way, injured by 

 the vast donations of land by the general government to these 

 States } I understand that the great north-west was ceded to the 

 nation for the benefit of all the people, by certain States having a 

 good claim to the same. The later acquisitions by purchase and 

 by conquest were all intended certainly for all the people. But in 

 what way are the people of Pennsylvania or of Virginia benefitted 

 by the school funds of Iowa or Nebraska, derived from the sale of 

 lands belonging to all the people .' These great land-grants are 

 but little understood by the people of the East. A few years ago, 

 when in Nebraska, I was told that the school lands of that State, if 

 laid out in a belt two miles wide, would extend from the Atlantic to 

 the Pacific Ocean. 



I believe in the aims of the Blair Bill most fully, but I think it 

 should be modified, in several particulars, i. The money should 

 be given to each State for the benefit of all school children in the 

 same, but with no other restrictions. 2. The western States should 

 receive no benefit from the grant until the old States have been 

 granted sums to counterbalance the grants to the western States. 



It is certainly a grave mistake on the part of our rulers to collect 

 vast sums of money, more than are needed to conduct the govern- 

 ment in an economical manner, but when once it is collected it 

 should be returned in the most direct manner possible. 



The South needs the aid. With ungallant restrictions removed, 

 she will accept and make good use of it, I feel as sure as I do that 

 it would do good in my own State. Geo. G. Groff. 



Bucknell University, Lewisburg, Penn. 



Wind Pressure and Velocity. 



Referring to Mr. H. Allen Hazen's letter in your issue of the 

 2d inst., I beg to call attention to the fact that the temperature of 

 the wind enters as an important factor in the determination of the 

 pressure due to a given velocity. In 1876 (Engmeering and 

 Mining Journal) I first pointed out that a variation in temperature 

 from 0° F. to 100° F. produces a difference in the amount of pres- 

 sure, for a given velocity of wind, of over one-fifth the total amount. 

 I have since discussed the subject more fully in a little treatise on 

 ' The Windmill as a Prime Mover ' (New York, John Wiley & 

 Sons, 1885), giving detailed formulse and complete tables, showing 

 the relation between the pressure and velocity of wind. 



Further accurate experimental determinations are certainly neces- 

 sary, but all data entering the problem (among them, the temper- 

 ature of the impinging air) should be carefully noted, and given due 

 weight in any generalization drawn from the experiments. 



Alfred R. Wolff. 



New York, Sept. 5. 



