September 8, 1892] 



NATURE 



455 



the rim exceeded the crater in bulk sufficiently to indicate a 

 mass of matter in the rim larger than would be caused by the 

 displacement of the material removed from the crater. Both 

 these surveys, however, gave negative results. The magnetic 

 survey indicated that if any considerable mass of iron exists 

 there it is buried at least fifty miles deep, and a comparison of 

 the quantity of matter in the rim shows no more than would fill 

 up the space of the crater. He was compelled, therefore, to 

 abandon the meteoric theory, notwithstanding that the chances 

 of the fortuitous concurrence of such a crater accompanied by 

 such a meteoric downfall is only one in five thousand. The 

 origin of the butte must therefore be an explosion of steam. 



The president elect of the Association, Prof. William 

 Ilarkness, of Washington, was born at Ecclefechan, Scotland, 

 in 1837, where his father, Rev. James Harkness, resided till 

 1839, when the family removed to America. The father was 

 for a while pastor of a church at Rochester, where the son was 

 educated, after having spent part of his college life at Lafayette 

 College, in Pennsylvania. He graduated at the University of 

 Rochester in 1858, and received from the same university the 

 degree of doctor of laws in 1874. It was, therefore, peculiarly 

 appropriate that he should be elected to the presidency at the 

 Rochester meeting. 



Prof. Harkness studied medicine, and practised as an army 

 surgeon in 1864 ; but, with the exception of a short time in the 

 army, he has been employed by the Government as an 

 astronomer for about thirty years. During the total eclipse of 

 1869, he discovered the 1474 line of the spectrum of solar pro- 

 tuberances. He became prominent in observations of the 

 transits of Venus. 



It is difficult to select the most important and valuable papers 

 from the whole number of 182 read before the several sections, 

 but a few abstracts will be subjoined which appear to merit 

 notice. 



George E. Hale, of Chicago, read a paper before the 

 astronomical section on " The Spectroheliograph of the Ken- 

 wood Astro-physical Observatory, Chicago, and results obtained 

 in the study of the Sun." He described the ingenious apparatus 

 which he had invented and perfected for photographing the 

 faculae and protuberances of the sun. This apparatus gives by 

 far the most perfect pictures ever taken, and is the first which 

 has successfully photographed the bright spots, showing faculce 

 which the eye cannot detect. Means were devised for taking on 

 the same plate at one exposure both the faculse and the pro- 

 tuberances, and Prof. Hale exhibited the first complete picture 

 of the sun ever taken. Comparison with the best plates made 

 at the Lick Observatory showed the great superiority of the 

 work at Chicago. An observation of unusual interest was made 

 on July 15, 1892. A photograph of the sun showed a large 

 spot. A few minutes later another photograph was taken, 

 which, when developed, showed that the bright band had 

 appeared since the last exposure. Twenty seven minutes there- 

 after another photograph showed that almost the entire spot 

 was covered with brilliant faculse, which by the end of an hour 

 had entirely disappeared, leaving the spot as at the first 

 exposure. This indicates an eruption proceeding with inde- 

 scribable and inconceivable velocity. This disturbance seems 

 to be connected with magnetic disturbances and the brilliant 

 aurora noted the next day. The section, Arith much enthusiasm, 

 passed a vote of thanks to Prof. Hale for his researches. 



Edwin B. Froit read a paper on "Thermal Absorption in 

 the Solar Atmosphere." Among the interesting phenomena 

 observed were some cases where the umbra of sun spots radiated 

 more heat than the neighbouring photosphere, indicating either 

 that the dark spot is at a higher elevation than the surrounding 

 photosphere, and consequently loses less heat by absorption of 

 the sun's atmosphere, or that it is attended by an invisible 

 facula. 



Prof, R. S. Woodward described the iced-bar base apparatus 

 lately devised by him for the Coast and Geodetic Survey. This 

 is a line measure, micrometer microscope apparatus. The 

 measuring bar is of steel, five metres long, and its temperature 

 is kept constant by a packing of melting ice. The use of ther- 

 mometers is thus avoided entirely. From results submitted by 

 the author it appears that the total probable error of one measure 

 with this apparatus of a distance a kilometre or more in length 

 will not exceed one part in four to five millions. 



One of the most important uses to which Prof. Woodward 

 has applied the iced-bar apparatus is that of showing that long 

 steel tapes, when properly handled, will give from one measure 



NO. II 93, VOL. 46] 



the length of a line, a kilometre, or more long with a probable 

 error not exceeding one part in a half-million. Considering that 

 this can be done at the rate of two kilometres per hour with a 

 100-metre tape, it would seem that such tapes must soon take 

 high rank amongst apparatus for measuring bases. 



Prof. W. A. Rogers read two papers before Section D, the 

 first of which was a description of a standard yard and metre 

 upon polished steel. The standard, which was exhibited, had 

 upon one edge a metre subdivided by 20 millimetres and 40 

 inches subdivided to tenths of inches. Both are standard or 

 62" Fahr. It appears from an investigation of these standards 

 that 772 of the separate millimetres have errors not exceeding 

 one mikron, and that of the 400 tenthof-inch spaces 280 have 

 errors not exceeding one-twenty-five-thousandth of an inch. 



Prof. Rogers read a second paper on an investigation of a 21- 

 foot screw. This screw was made by the Pratt and Whitney 

 Company for R. Hoe and Co., of New York. It appeared 

 from this investigation that the pitch of this screw was very 

 regular in its character, but that the linear error amounted to 

 nearly one-hundredth of an inch in 21 feet. A part of this is 

 undoubtedly due to flexure, but a part is due to changes of pitch 

 in the screw itself. 



In the section of anthropology Permanent Secretary F, W. 

 Putnam gave an interesting talk on "Copper Implements and 

 Ornaments in the Ohio Mounds." He emphatically denied the 

 statements that these copper instruments were fashioned by white 

 men and given to the Indians in trade. " It must be," said he, 

 "that these implements were made by the native Americans. In 

 all cases where implements and ornaments are found in these 

 mounds there are found also on the altars nuggets of copper. 

 So it is with the silver implements and those made of meteoric 

 iron. Now, is it likely that the trader would furnish the Indian 

 with nuggets of the natural material ? There is conclusive proof 

 that the original settlers of the Ohio Valley worked the metal 

 into these implements and ornaments. Again, many of these 

 mounds have trees growing on them that are between 400 and 

 500 years old. This carries them back beyond the time of 

 trading." Prof. Putnam explained that holes could be cut in 

 the sheet copper which had been hammered out by the Indian 

 by simply placing the sheet of copper on the trunk of a tree 

 and pounding into it one end of an oak limb squared. He was 

 unable to describe the probable mode adopted by the Indians in 

 cutting edges shaped like the teeth of a saw, but thought it was 

 done by the use of an instrument made of meteoric iron. 



In the section of biology, C. V, Riley read a paper on "Fer- 

 tilization of the Fig and Caprification." In the production of 

 the best Smyrna figs certain minute insects perform an essential 

 function in fructifying the fig. The process is called " caprifica- 

 tion," and has been performed by the aid of fig-growers ever 

 since the time of Aristotle, The cultivator is accustomed at a 

 certain season to place the fruit of the "caprifig," which con- 

 tains these insects, on the fig tree which contains the edible fig. 

 The caprifig does indeed produce a fig, but it is small and insipid. 

 The tree which produces the edible fig does not yield fruit of fine 

 flavour unless it is thus fertilized by the aid of these insects, the 

 scientific name of which is Blastophaga psenes. The absence of 

 these explains the insipidity of figs raised in California, There 

 are, indeed, a dozen species of Blastophaga found in America, 

 but it is improbable that any one of them is adapted to the fer- 

 tilization of the Smyrna fig, which growers there are trying to 

 cultivate. The caprifig, however, is already well established, 

 and the desideratum seems to be to introduce the insects. This, 

 Prof. Riley thinks, can be done by gathering the fruit contain- 

 ing them in Smyrna and rapidly transporting it to Calirornia, 

 which, he urges, should be undertaken by the Government. An 

 attempt was made last summer by J. Shinn, of Niles, Alameda 

 County, California. . The fruit containing insects was gathered 

 at Smyrna in the last days of June Jand received at Niles on 

 July 23, within twenty-five days, but it is not known whether the 

 experiment was successful. 



Jn the section of physics, several valuable papers were contri- 

 butedbyG. W. Hough, A. E. Dolben, W. L. Stevens, E. L. 

 Nichols, B, W. Snow, and others. One of the most interesting 

 papers giving results of original research was by Edwin S. Ferry 

 on "Persistence of Vision." 



Prof, Frank P. Whitman, in a brief paper on the " Magnetic 

 Disturbances caused by Electric Railways," gave the following 

 results of recent observations : — "No magnetic instruments de- 

 pendent on the earth's field can be used for reasonably accurate 

 work at less than 1500 feet from an electric railway, and the 



