Jjine 2 1, 1877] 



NA TURE 



149 



cover several distinct researches, as follows : — (i) On sun-spots 

 and chromosphere, conducted by the late Prof. Winlock ; the 

 results are published, with plates, in the transactions of the 

 Harvard Observatory. (2) Magnetic survey of the United States, 

 in charge of Prof. J. E. Hilgard ; during the year twenty-6ve 

 new stations in New Kngland and Lower Canada have been 

 occHpied ; at all the stations the dip, declination, and horizontal 

 intensity are observed. (3) Comparisons of sensations of light ; 

 in charge of Mr. Charles S. Peirce. The object is especially to 

 ascertain the mathematical formula connecting the capacity of 

 the eye for light sensations with the physical variations of radia- 

 tion ; two sensations are compared, the one fixed, the other 

 variable ; part of the results have been published. (4) Researches 

 on the distribution of heat on the solar surface, the laws of its 

 radiation and absorption, and effects on terrestrial climate ; con- 

 ducted by Prof. S. P. Langley. (5) Researches on the laws of 

 sound and the duration of vibrations of tuning-forks ; conducted 

 by Prof. A. M. Mayer. The work of utilising the observations 

 made on the transit of Venus is under direction of a committee 

 of which the president of the Academy is a member ; progress 

 has been made in this work, but it is scarcely yet ready for 

 report. The endeavour to obtain an appropriation for a per- 

 manent building to display the scientific and other material con- 

 tributed by the Government of the United States and other 

 nations during the Centennial Exhibition, failed to obtain a two- 

 thirds vote in the House of Representatives after passing the 

 Senate without dissent. The effort will be renewed at the next 

 ses>ion of Congress. The collections are large, valuable, and 

 instructive, including the costly gifts of other nations, and the 

 entire exhibit that was in the "Government Building " at Phila- 

 delphia. 



During the meeting the members of the Academy were formally 

 invited to visit the President of the United States at the White 

 House. They were duly presented, and President Hayes ex- 

 pressed himself in a brief speech as fully appreciating the value 

 of scientific pursuits, and wilhng and desirous to advance the 

 interests of science. The reception was notably pleasant and 

 cordial. 



We give abstracts of the more important communications : — 

 Prol. Alexander Asjass z gave a brief notice of researches on 

 the young stages of some osseous fishes. The history of previous 

 researches on these points, since those of von Baer at the be- 

 ginning of this century, was reviewed. Prof. Aga.ssiz concludes 

 that with few exceptions the tail begins to be formed below the 

 dorsal cord. I( embiyos and very young animals are examined, 

 a lobe is found much developed in some and common to all. 

 The tail fin and the anal fin are probably modifications of the 

 same organ. There is a general uniformity in the plan of con- 

 struction of the tails of fi-hes whether osseous or otherwise. 



Under the title of " Some Results of Deep-sea Dredging," 

 Prof Agassiz stated views partly founded upon his general know- 

 ledge and study of the products and observations made during 

 the Challenger expedi'ion, and partly up jn information obtained 

 in conversations with Prof. Sir C. Wyvdle Thomson and other 

 members of the expedition. The fact of a point of zero tempera- 

 ture being in all uceans but varying in depth with latitudes, had 

 been indicated by previous expeditions and was fully established 

 by the Challenger obstrvations. At the equator a depth of 500 

 fathoms is needed to reach this zero line ; as we approach the 

 pules the depth of this line decreases till at last it is at the sur- 

 face. Sometimes the temperature of the lower water is 2° or 3" 

 below zero, but the conditions are, in general, uniform. Equally 

 uniform is the fauna below this line. Above it, the arctic, tem- 

 perate, and tropical faunas ara clearly distinguishable from each 

 other. There is a remarkable uniformity among the animals 

 of the tropical fauna, such as may have resulted if in a 

 previous era the isthmuses of Darien and Suez were absent, the 

 Sahara was covered by the sea, and an equatorial current swept 

 freely around the world. The deep-sea fauna is so singularly like 

 the cretaceous that its forms would have been at once assigned 

 to that epoch by most palaeontologists if they had been fossil. 

 The similarity if not identity of these forms indicates that there 

 has been scarcely any change since that era. This is true of 

 echinoderms, worms, and even of some fishes. It is equally 

 true of s. me shore anin als found both otT our coasts and in the 

 chalk. These have been subjected to the most varied conditions 

 of existence as compared with their ancestors, and yet have not 

 altered. There is evidence that natural selection, even under 

 conditions where its forces are extreme, may not bring about any 

 change. The present continents are probably much older than 

 has bter. s ipposed. There is anen'irc wan^ of evidence that 



great continents existed where oceans now are. The shore mud 

 from our continents is washed down comparatively only a few 

 miles from shore ; the depths are not reached by this mud. 

 Other well-known theories need to be modified. At a depth of 

 2,500 feet Crustacea are found having good eyes. These organs 

 have undergone no change during innumerable centuries. There 

 are similar facts established as to starfish. There is no very great 

 number of blind animals in the ocean depths. Those that are 

 blind need not be classed as retrogressions from ancestors that 

 had eyes. Both as to blind animals in the sea and those found 

 in caves, it seems most probable that they were the descendants 

 of eyeless ancestors. In the discussion which followed this 

 C'lmmjnication, Prof. Agassiz said that he had long doubted 

 the theory of geologists respecting an immense miocene con- 

 tinent. 



Prof. Joseph Le Conte, of Oakland, California, furnished a 

 paper on critical periods in the history of the earth and their 

 relation to evolution ; and on the quaternary as such a period. 

 This paper instanced and enlarged upon the breaks in the geo- 

 logical and palKontological records, and argued that a more 

 rapid rate of evolution had been operative during the intervals, 

 which he designated as "critical periods." The quaternary era 

 he regarded as one of these critical periods during which rapid 

 changes had taken place, but it differed from most of such periods 

 in the fact of its records being preserved. 



Prof G. K. Gilbert described the characteristics and mode of 

 formntion of the Henry Mountains. 



Dr. F. V. Hayden described the results of boring artesian wells 

 in a locality near Rawlins Springs in Wyoming Territory on the 

 line of the Union Pacific Railroad. The district is on the 

 dividing line of the watershed of the continent, some of the 

 streams on the sides of the district flowing to the Atlantic, and 

 some to the Pacific oceans. The rainfall of the district is very 

 small — not over six to ten inches per year. The wells were 

 bored to depths varying from 300 to over 1,000 feet. The water 

 obtained was from 1,000 to 2,000 gallons per hour ; it waslit'ted 

 by pumps driven by windmills. The result showed the feasibi- 

 lity of thus irrigating very arid regions. The wells were bored 

 under Dr. Hayden's direction, in a sinclinal basin which he 

 regarded as of tertiary formation, probably eocene ; but paljeon- 

 tologists who had examined its fossils had pronounced them 

 cretaceous. Dr. Hayden regarded this as an instance where the 

 chasm between the cretaceous and tertiary rocks was bridged 

 over ; he stated that the rocks were consecutive from cretaceous 

 to middle tertiaiy. This opinion was not fully ^hared by the 

 other geologists present, and the discussion which followed 

 became exceedingly animated, as it brought up qucitions long at 

 issue between the respective students of the rocks and of the 

 fossils of that region. 



Major J. W. Powell presented some remarkable facts respect- 

 ing the public domain of the United States. Dividing the 

 United States into two portions, the humid, where the rainfall 

 is sufficient for agriculture, and the arid, where it is not, the 

 latter is found nearly to equal the former. 



Prof. Elias Loomis, of Yale College, contributed his seventh 

 paper of a series entitled " Contributions to Meteorology," this 

 paper continuing the investigation of rain areas which was begun 

 m the last. Prof. Loomis selected all the cases in the United 

 States during fifteen months — September 1872, to November 

 1S73 — in which the reported rainfall amounted to at least eight 

 inches in eight hours. For each of these cases the curves of 

 equal rainfall were drawn on the map and compared. The form 

 of these curves, though occasionally irregular, in general approxi- 

 mates an ellipse, of which the major axis is i ot quite double the 

 minor. In these cases the area of one-inch rainfall exceeded in 

 length 500 miles ; in six cases of one-half-inch rainfall 750 miles; 

 frequently the entire area is an oval of more than 1,000 miles 

 length and exceeding 500 miles breadth. In general the rain 

 area centre is east of the low pressure centre, but in several 

 instances the reverse was the fact, and in some cases the rainfall 

 appeared to have had decided influence on the storm's progress, 

 as to its direction. It was concluded that rainfall is not essential 

 to low barometer areas, nor the chief cause of their formation or 

 progressive motion. Such areas result from a general atmo- 

 spheric movement toward a central area, and may be caused l>y 

 unequal barometric pressure, unequal temperature, or unequal 

 amounts of aqueous vapour. The two last-named causes are not 

 comparable to the first of the three in cogency, and only deflect 

 i the winds slightly. The progress of areas of low barometer in 

 all latitudes is mainly determined by the same causes as those 

 „hicli determine the get^eral atmo;pheric circulation ; their 



