48 SCIENCE ASSOCIATIONS. 



ASTRONOMICAL PROGRESS. 



Mendelejeff's law, was commended, and used 

 for the advancement of the speaker's ideas. 



The president's address in Section C, devoted 

 to geology, was given by Prof. T. J. Bonney on 

 " The Application of Microscopic Analysis to 

 Geology." It was based largely on the fact that 

 the physical or mechanical changes in particles 

 of agglomerated rocks could be determined by 

 the microscope. In quartz'tes and sandstones 

 the attrition received by the grains before ag- 

 glomeration could thus be studied, illustrating 

 their origin, the wind and water action to 

 which they had been subjected, the distance 

 traveled, etc. The rocks of England were con- 

 sidered from this standpoint, and deductions 

 made in conclusion as to points in their physi- 

 cal geology. 



The president's address in Section D, de- 

 voted to biology, was given by Prof. William 

 Carruthers on " The Relation of Existing Vege- 

 tation to Past Flora." The material could not 

 be found in herbariums, as the oldest in exist- 

 ence only dated back to 1646. But specimens 

 from the sepulchres of Egypt collected and pre- 

 pared by Dr. Schweinfurth had given the finest 

 material for this work. He had found in the 

 wreaths and floral decorations of mummies 

 samples that, treated with hot water, could be 

 perfectly mounted, in some cases giving the 

 color of the original. These were supplement- 

 ed by specimens from American mounds and 

 Swiss lake-dwellings, and showed no difference 

 of any moment from existing vegetation. Even 

 seeds of weeds that to-day annoyed cultivators 

 were found mixed with wheat and flax-seed 

 from these sources. Hence the conclusion was 

 drawn that species must be dealt with as fixed 

 quantities. The conclusion was in the line of 

 Prof. Dawson's argument. 



Section E, devoted to geology, was presided 

 over by Maj.-Gen. Sir F. J. Goldsmid, who in 

 liis address made a plea for the more thorough 

 teaching of this science in the schools. 



In Section G, devoted to mechanical science, 

 Sir James N. Douglass delivered the president's 

 address, on lighthouses. Some interesting 

 dates were first given, and experiments with 

 different lenses and lights, and the system of 

 photometry, were described. The conclusions 

 definitely reached by the highest authorities, 

 and that might be considered settled, were that 

 for ordinary purposes mineral oil was most 

 suitable and economical, and for headland 

 lights electricity was best. 



The president's address in Section H, de- 

 voted to anthropology, was delivered by Sir 

 George Campbell. He advocated a more popu- 

 lar study of the science, claiming that popular 

 data were the best, and were superior to cra- 

 niology and the more abstruse methods. In- 

 dia was mentioned as a field fcr the study. 

 The good to be done in elevating the race of 

 man by scientific intermingling of different 

 races was spoken of, we having no reason to 

 believe that man has made any advance in the 

 past 4,000 or 5,000 years. Some of the general 



race tendencies were considered, as that of the 

 English to misplace the aspirate. A more uni- 

 versal study of practical anthropology was final- 

 ly recommended. 



Among the many numerous reports of com- 

 mittees, those " On Fossil Plants in the Tertiary 

 and Secondary Beds of the United Kingdom," 

 " On the Caves of North Wales," and " On the 

 Depth of Frozen Soil," may be particularly al- 

 luded to. Grants aggregating 1,300 were 

 made to the committees for work in the ensu- 

 ing year. 



ASTRONOMICAL PROGRESS AM) PHENOMENA. 

 The progress in astronomy, both theoretical 

 and observational, during the past twelve 

 months, appears to have been equal to that of 

 any recent year. 



The Solar Parallax. The determination of the 

 earth's distance from the sun, the late astrono- 

 mer royal pronounced the grandest problem 

 of astronomy. It was formerly supposed that 

 the transits of Venus furnished the most trust- 

 worthy data ; but the results of four transits 

 have been very discordant, and as another will 

 not occur until after the lapse of one hundred 

 and eighteen years, astronomers have turned 

 their attention to other, and, it may be, more 

 exact processes. The determination of the ve- 

 locity of light gives, perhaps, the most accu- 

 rate value of the sun's distance of any that 

 have been tried, and, as between that and 

 other methods, there is happily a close agree- 

 ment, which lends an additional assurance 

 that, within narrow limits of error, the solar 

 distance is known. Adopting 20-492" as the 

 constant of aberration, Prof. Newcomb makes 

 the velocity of light in vacua 299,860 kilome- 

 tres (= 186,330 miles) a second. Taking the 

 earth's equatorial radius as 3,963'296 miles, 

 gives the solar parallax the value of 8*794, and 

 the sun's mean distance from the earth, in 

 round numbers, 93,000,000 miles, which is the 

 base-line for all celestial measurements except 

 those relating to the moon. The official soLir 

 parallax adopted in England, is 8 - 848", being 

 the result of the reduction of all the observa- 

 tions of the transit of Venus of 1874. But 

 from Dr. Gill's observations of Mars, and of 

 some of the asteroids at their oppositions 

 while in perihelion, this parallax is too large; 

 and he strenuously contends for one smaller 

 and more nearly conformable to that obtained 

 by Prof. Newcomb. This corrected value 

 somewhat reduces the supposed solar diame- 

 ter, making a second of arc on the sun almost 

 exactly 450 miles instead of 460, as resulted 

 from the old assumed distance of 95,000,000 

 miles. It also diminishes the computed dis- 

 tance of all the stars, and the magnitudes and 

 distances of all the planets from the sun, and 

 of the satellites (except our own), from their 

 primaries. 



The San. In all ages, the cause of the sun's 

 heat, light, and actinism, as well as of his spots, 

 has been a fruitful theme for the study of 

 physicists. But few theories to account for 



