162 



SCIENCE. 



[Vol. VIU., No. 185 



methods, and the new questions raised by investi- 

 gation, many series of experiments will be under- 

 taken, the outcome of which will definitely settle 

 the question of the entrance of free nitrogen into 

 vegetable tissues. If this question be answered af- 

 firmatively, agricultural science will not place 

 bounds to the possible production of foods. If the 

 nitrofying process does go on within the cells of 

 plants, and if living organisms do fix free nitrogen 

 in the soil in a form in which at least a portion of 

 it may be nitrified, we may look to see the quanti- 

 ties of combined nitrogen increase paW jaassM with 

 the needs of plant life. Thus, even intensive cul- 

 ture may leave the gardens and spread over the 

 fields, and the quantities of food suitable for the 

 sustenance of the human race be enormously in- 

 creased. 



In regarding the agricultural economies of the 

 future, however, it must not be forgotten that a 

 certain degree of warmth is as necessary to plant 

 development as potash, phosphoric acid, and ni- 

 trogen. If it be true, therefore, that the earth is 

 gradually cooling, there may come a time when a 

 cosmic athermacy may cause the famine which 

 scientific agricultui-e will have prevented. Fortu- 

 nately, however, for the human race, the cereals, 

 the best single ai'ticle of food, are peculiarly suit- 

 able to a cold climate. Barley is cultivated in 

 Iceland, and oatmeal feeds the best brain and 

 muscle of the world in the high latitudes of 

 Europe. 



It is probably true that all life, vegetable and 

 animal, had its origin in the boreal circumpolar 

 regions. Life has already been pushed half way 

 to the equator, and slowly but surely the armies of 

 ice advance their lines. The march of the human 

 race equatorwards is a forced march, even if it be 

 no more than a millimetre in a millenium. Some 

 time in the remote future the last man will reach 

 the equator. There, with the mocking disc of the 

 sun in the zenith, denying him warmth, flat- 

 headed, and pinched as to every feature, he will 

 gulp his last mite of albuminoids in his oatmeal, 

 and close his struggle with an indurate in hospi- 

 tality. 



NOTES AND NEWS. 

 According to the report of Gustavus Hinrichs 

 of the weather service of Iowa, that state, since 

 the middle of May, has been subjected to a drouth, 

 the most severe on record. The most serious 

 drouth preceding the present one prevailed during 

 June and July of 1863, when for sixty days no 

 serviceable rains fell in Iowa City ; but rains had 

 been sufficiently abundant till the end of May, 

 and nearly five inches of water fell during the 

 first ten days of August. In the early summer of 



1886, the last good rain fell on May 13. After 

 that time, there was no rain reaching half an inch 

 until August 4, — eighty-three days without a 

 serviceable shower ! The total rainfall during 

 that period was less than one inch, while the nor- 

 mal rainfall would be nearly ten and a half inches. 

 But, notwithstanding this extreme drouth, it can- 

 not be said that there is a failure of crops ; because 

 farming operations in that state are so diversified 

 that a total failure is almost an impossibility. 



LETTERS TO THE EDITOR. 



*t* Correspondents are requested to be as brief as possible. The 

 writer's name is in all cases required as proof of good faith. 



Glaciers and glacialists. 



The number of Science for the 23d of July last con- 

 tains a paper by Mr. Jules Marcou, in which he refers 

 to my memoir on Professor Guyot (published by the 

 U. S. national academy), and denies statements cited 

 by me from a publication by Professor Guyot with 

 regard to the latter's glacier discoveries. Mr. Marcou 

 commences his criticism on the subject with the fol- 

 lowing paragraph: "At Princeton Guyot was long 

 isolated from intercourse with Swiss naturalists ; and 

 at the close of his life, while suffering under the mal- 

 ady which proved fatal in 1884, he put forth claims 

 of doubtful value. These are the facts." Then 

 follow the facts as Mr. Marcou understands them. 



Mr. Marcnu's statement is wrong in important 

 points. Professor Guyot gives an account of his own 

 discoveries of 1838 in his memoir of Professor Agas- 

 siz, which v.'as read before the national academy, the 

 first part in October, 1877, the second in April, 1878. 

 This is six years before his decease, while he was still 

 engaged in his laborious topographical survey of the 

 Catskills The following is the paragraph from the 

 Agassiz memoir : — 



" In the spring of 1838 I had the pleasure of a visit 

 from my dear friend Agassiz in Paris, where I then 

 resided. The main topic of conversation was, of 

 course, the glaciers He put me au courant of Char- 

 pentier's views, as yet imperfectly published (his book 

 havin^r been issued only two years later, in 1840), 

 and adding his own idea of a general glacier era, he 

 urgied me to turn my attention to these phenomena. 

 I asked to be allowed to suspend my judgment until 

 my own observations should justify ray adhesion to 

 so startling a theory, but promised to visit the gla- 

 ciers that very summer. I did so, and an exploring 

 tour of six weeks in the Central Alps rewarded me 

 beyond my expectation. The glacier of the Aar, on 

 ■which Agassiz began two years later (1840) his regu- 

 lar system of observations, taught me the law of the 

 moraines. The glacier of the Rhone gave me the 

 law of the more rapid advance of the centre of the 

 glacier, and that of the formation of the crevasses, 

 both transversal and longitudinal. The glacier of 

 Gries showed me the laminated, or ribboned (blue 

 bands) structure of the ice deep down in the mass of 

 the glacier, and the law of the more rapid advance of 

 the top over the bottom. On the southern slope of 

 Mont Blanc, the great glacier of La Brenva, with its 

 twin rocks, rising like two dark eyes from the mid- 

 dle of the ice (they are, indeed, called by the moun- 

 taineers the * eyes of the glacier '), made me under- 

 stand that the motion of the glacier takes place by a 

 gradual displacement of its molecules under the influ- 

 ence of gravity, giving it a sort of plasticity, and not 



