August 20, 18S6.J 



SCIENCE. 



159 



conditions necessarily indicated by the moraine- 

 heading coarse gravel streams ; and herein lies an 

 important discrimination of the drainage and 

 ■orographic attitudes of the two glacial epochs. 



In addition to the tili-lilse phases previously 

 noted, two assorted deposits were considered. 

 They range in altitude from below the sea-level to 

 three thousand feet and beyond, and vary greatly 

 in individual extent. The great examples are the 

 immense sheets of assorted drift overspreading the 

 great basins of the St. Lawrence, and the Winni- 

 peg basin. These often present, among their 

 surest credentials, overflow channels to the south- 

 ward, crossing divides often hundreds of feet above 

 existing outlets, and varying in altitude among 

 themselves at least two thousand feet. Some of 

 the more important were enumerated. Reference 

 ■was also made to the iceward termination of these 

 lacustrine deposits, a phenomenon yet but partially 

 studied. The surfaces of these ancient lakes not 

 only stood at altitudes greatly different from the 

 present, but were tilted, if not distorted, as com- 

 pared with existing water levels, rising as a gene- 

 ral rule, toward the north. Data are being 

 rapidly gathered, in the effort to determine how 

 much of this was due to ice attraction, to ice 

 V7eighting, to thermal changes, to intercurrent 

 crustal changes independent of glacial presence, 

 and to other and undiscovered causes. Reference 

 ■was made to the scorings which the glacial floor 

 presents, and some of the more remarkable features 

 alluded to. The number of recorded observations 

 of striae reaches nearly three thousand. 



Turning to the more purely intellectual products 

 springing from the glacial phenomena, it was 

 noted that our former ample assortment of theories 

 of the origin of the drift has become practically 

 reduced to one, — the glacial. With few excep- 

 tions, the investigators of glacial phenomena in 

 the United States accept as demonstrated the 

 glacial origin of the greater mass of the drift. 

 This is less true of Canadian investigators. Sub- 

 ordinate to this dominant hypothesis, there are 

 various degrees of belief respecting the extent of 

 auxiliary glacio-natant agencies. 



Our wealth of working hypotheses has increased 

 as our theory of genesis has become fixed upon the 

 fruitful doctrine of the glacier origin of the drift. 

 The recent introduction of strictly glacial methods 

 has been prolific in stimulus and in interpretation. 

 The working hpotheses necessary for the tracing 

 out of moraines, the discrimination of the tills, 

 the differentiation of the kames, osars, and similar 

 products, and for the analysis of the drainage 

 phenomena, have become rich beyond the limits 

 •of convenient statement, and suggestive to a de- 

 gree unimagined a decade since. Under these. 



the advance of a year is becoming as the advance 

 of a decade. 



If we turn to the broader speculations respecting 

 the origin of the glacial epoch, we find our wealth 

 little increased. We have on hand practically the 

 same old stock of hypotheses, all badly damaged 

 by the deluge of recent facts. The earlier theory 

 of northern elevation has been rendered practically 

 valueless ; and the various astronomical hypothe- 

 ses seem to be the worse for the increased knowl- 

 edge of the distribution of the ancient ice sheet. 

 Even the ingenious theory of CroU becomes in- 

 creasingly unsatisfactory as the phenomena are 

 developed into fuller appreciation. The more we 

 consider the asymmetry of the ice distribution in 

 latitude and longitude, and its disparity in eleva- 

 tion, the more difficult it becomes to explain the 

 phenomena upon any astronomical basis. If we 

 were at liberty to disregard the considerations 

 forced upon us by physicists and astronomers, and 

 permit ourselves simply to follow freely the ap- 

 parent leadings of the phenomena, it appears at 

 this hour as though we should be led upon an old 

 and forbidden trail, — the hypothesis of a wander- 

 ing pole. It is admitted that there is a vera causa 

 in elevations and depressions of the earth's crust, 

 but it is held inadequate. It is admitted that the 

 apparent changes of latitude shown by the deter- 

 minations of European and American observatories 

 are remarkable, but their trustworthiness is chal- 

 lenged. Were there no barriers against free hypo- 

 theses in this direction, glacial phenomena could 

 apparently find adequate explanation ; but de- 

 barred — as we doubtless should consider ourselves 

 to be at present — from this resource, our hypothe- 

 ses remain inharmonious with the facts, and the 

 riddle remains unsolved. 



THE ECONOMICAL ASPECT OF AGRICUL- 

 TURAL CHEMISTRY. 



Professor Wiley opened his address with sta- 

 tistics showing the value of the agricultural prod- 

 ucts of the United States, He then gave figures 

 showing the chemical constitution of the different 

 products, and laid stress upon the necessity of 

 supplying the growing crops with sufiicient potas- 

 sium, phosphorus, and nitrogen. The value of 

 the potash, phosphoric acid, and albuminoids or 

 nitrogen entering into a single harvest he esti- 

 mated as follows, valuing potash at five cents per 

 pound, phosphoric acid at six cents, and nitrogen 

 at eighteen cents. The total value of each of 

 these ingredients is, then, potash, $598,067,446 ; 



Abstract of an address delivered before the section of 

 chemistry of the American association for the advance- 

 ment of science at Buffalo, Aug. 19, by Prof. H. W. Wiley of 

 the agricultural department, vice-president of the section. 



