Oct. 1, 1874 1 



NA TURE 



441 



being prepared at Vienna to start next summer. One 

 half of the expedition will seek to advance to the north, 

 under Lieut. P.iyer, by way of East Greenland, and the 

 other half, under Count Wilczek, will proceed -uia 

 Siberia. The object of the expedition is to ascertain 

 if the newly-discovered Franz-Joseph Land is a con- 

 tinent or an island. 



THE AMERICAN ASSOCIATION FOR THE 



ADVANCEMENT OF SCIENCE 



'T'HE twenty-third meeting of this Association, which com- 

 -'• menced at Hartford, under the presidency of Dr. J. L. Lc 

 Conte, on Aug. 12, seems to have been a successful one. 

 Apart from the regular growth in prosperity which is exhibited 

 every year, there was the unusual accession of the cliemists, 

 who have resolved to make their science strongly represented, and 

 there was the excitement and interest which attended an impor- 

 tant change in the constitution of the Association. The nature of 

 the change \:'e Iiave already indicated (vol. x. p. 3S2). There 

 was an unusually large attendance of the most eminent American 

 representatives of science. The Association meets at Detroit 

 next year on the second Wednesday of August. 



The president's address consisted chiefly of allusions to some 

 ofthe principal scientific events of the year, andofasummary of the 

 matters to come before the Association. At a later period of 

 the meeting the retiring president gave his address, in which he 

 reviewed the progress of scientific instruments and methods. 

 We can only refer very briefly to some of the more important 

 jiapers read. 



In a paper On tlu Periodicity of the Rainfall in the United 

 States in Relation to the Periodicity of the Solar Spots, by Prof. 

 John Ihocklesby, the author concludes from his investigations 

 tliat in the United States there is a connection existing between 

 rainfalls and variations in tlie sun-spot area ; the rainfall rising 

 above the mean when the sun-spot area is in excess and falling 

 below it when it is deficient. 



Differential Measiirctnents of Solar Temperature, by Prof. S. P. 

 Langley of Pittsburgh, Pa. After stating the aims of the 

 Alleghany Observatory at Pittsburgh, and giving details of the 

 work now carried on there, consisting largely of observations and 

 photographs of the sun. Prof. Langley said that there is a very 

 wide variation in both the heat and light, and probably also in 

 the actinic force of different parts of the sun. The difference is 

 due principally, but not wholly, to differences in atmospheric 

 absorption. Prof Henry observed that the image of a sun-spot 

 is colder than the photosphere surrounding it. Secchi has shown 

 that the heat of the sun diminishes as we approach its edge, and 

 lie thinks that there is a different temperature at the sun's 

 equator and the poles. Prof Langley gave details of his own 

 experiments with a thermopile upon these points. He finds that 

 the observation of Prof. Henry is correct. But comparing the 

 image of the spot with the photosphere immediately surrounding 

 it, he finds that the image of a spot not far from the centre is 

 uniformly warmer than that of the edge. To get the full signi- 

 ficance of this observation we must consider that the image of the 

 same spot is at the same time darker and colder than the photo- 

 sphere near the centre, and darker and warmer than the photo- 

 sphere near the edge. A series of measurements of the heat from 

 the centre to the edge were made. 



It does not appear as the result of these experiments that there 

 is so great a selective absorption of heat in die lower regions of 

 the sun's atmospliere, that when rays come from the edge of the 

 disc and pass through a greater proportional tliickness of his 

 atmosphere, the heat is filtered from them and the light allowed 

 to go through. We find that the heat falls away so very rapidly 

 towards the edge as to indicate a much greater thinness of the 

 solar chromosphere than has been hitherto admitted. We appear 

 to have been led to the conclusion that there is a local obscura- 

 tion over the spot very remarkable both in degree and kind. 

 Prof Langley exhibited a photograph of a sun-spot that looked, 

 he said, like a sketch of a crystallising substance ; when, however, 

 we consider the enormous areas involved, we find the analogies 

 of crystallisation wholly fail us, and we may more probably 

 account for the facts by a hypothesis of cyclonic action. He con- 

 cluded by pointing out the great value of these studies in connec- 

 tion with investigations in terrestrial meteorology. 



Distribution of the Poles of Nelnthe, by Prof Cleveland Abbe, 



of Washington. Tlie general problem attacked in the present 

 paper is the question whether there are planes that have a 

 definite relation to nebula?. 



It may in general be stated that the positions of planes ot 

 rotation among the nebulae do not show any such uniformity as is 

 the case with the solar system : on tlie contrary, they are at all 

 possible angles with each other. But there is this remarkable 

 feature : that their nodes cluster about a point in R.A. I2h. 45m. 

 and declination 60° N., that point being the North Pole of the 

 plane near which he the majority of the so-called axes of rota- 

 tion. 



Cave Fauna of the Middle Slates, by Prof A. S. Packard, jun., 

 of Salem, Mass. — For about a month during the last part of 

 April and early in May last, Prof Packard was engaged with 

 Mr. T. G. Sanborn in exploring the caves of Kentucky under 

 the auspices ofthe Geological Survey of that St.ate, Prof Shaler 

 accompanying Prof Packard. They first examined the Mammoth 

 Cave, and doubled the number of animals known to exist therein 

 and in others adjoining. An exploration, with Prof Shaler, of 

 the Carter Caves in Gr.iyson County, Ky. , also revealed a rich 

 fauna composed of twenty species. Prof Packard also examined 

 Wyandotte Cave alone, and found a wingless Procus and two 

 species of Thysanura new to tlie cave. Several caves within six- 

 teen miles of New Albany, Ind., at Bradford, were examined. 

 Finally, a careful examination of Weyer's Cave, in Virginia, 

 and the adjoining Cave of the Fountains revealed a fauna con- 

 taining some twenty species, no life having been previously 

 reported from those caves. 



These results show a great uniformity in the distribution of 

 life — more than would at first be expected, though these caves 

 lie in a faunal region nearly identical as regards the external 

 world, and the temperature of the , caves is very constant. Still 

 some notable differences occurred. 



Change hy Gradual Modification not the Universal Law, by 

 Thomas Meehan, of Germantown, Penn. — After adducing many 

 instances in support of the theory that new forms are often 

 generated by "leaps," Mr. Meehan concludes with the follow- 

 ing propositions: — I. Morphological changes in Individual 

 plants are not alw-iys by gradual modifications. 2. Variations 

 from specific forms follow the same law. 3. Variations are often 

 sudden and also of such decided character as to seem generic. 



4. These sudden formations perpetuate themselves similarly in 

 all respects to forms springing from gradual modifications. 



5. Variations of similar character occur in widely separated 

 localities. 6. Variations occur in communities of plants simul- 

 taneously by causes affecting nutrition, and perhaps by other 

 causes. Mr. Median argues from these premises that new and 

 widely distinct species may be suddenly evolved from pre-existing 

 forms without the intervention of connecting links. 



This piaper provoked considerable discussion. Prof. Morse 

 said that the impression seemed to prevail among a great many 

 that Prof. Meehan's paper was an argument against Darwinism, 

 while in reality, in whatever sense you look at it, it was a cor- 

 roboration ofthe theory of evolution. Prof C. V. Riley insisted 

 that most of the circumstances cited by Prof Meehan found their 

 parallels in what were generally known to zoologists as well as 

 botanists as "sports" or even "monstrosities," and that Mr. 

 Darwin himself had instanced some of the most interesting 

 cases. 



Prof Asa Gray remarked that he only wished to state in 

 respect to variations occurring abruptly as they did, that 

 those certainly were not the kind of things which Mr. Darwin 

 would have regarded as in any way interfering with his 

 view, and he did not think Mr. Sleehan had rightly compre- 

 hended thestatement to which he had called attention. " I think 

 (pursued Prof Gray) that the statement, whatever it is, taken in 

 connection with the remark which Mr. Riley made, and which 

 Mr. Darwin a good deal insists upon, viz., that he does not look 

 to monstrosities for the introduction of new forms, because the 

 monstrosities may be expected to be taken out of relation to the 

 surrounding circumstances, and that it is only those modifications 

 which are in relation to surroundiug and changing circumstances 

 that can be utilised and turned to account — is not to be found 

 fault with. Mr. D.arwin distinctly notes that monstrosities m.ay 

 be hereditary, and so may be supposed even to be cont nued if 

 they were sufficient in relation to surrounding circumstances. 

 So, if Mr. Darwin readily takes into his view changes like that 

 which everyone calls monstrosities, he may readily be expected 

 not to regard it as any infringement upon the maxim that varie- 

 ties should come into existence quite abruptly with considerable 

 differences. I think it is true that varieties are apt to arise in 



