310 



SCIENCE. 



[N. S. Vol. XXI. No. 530. 



photographic plates. In connection with the 

 spectrobolographic determinations of the solar 

 constant of radiation at the Smithsonian Ob- 

 servatory, it is desired to know the variations 

 in ordinates of holographic curves correspond- 

 ing with the intensity of rays of different 

 wave-lengths in the solar spectrum, and fur- 

 ther to sum up the areas included under such 

 curves corresponding to the total energy of 

 radiation reaching the bolometer. 



The machine shown was constructed after 

 Mv. Abbott's general design by Warner & 

 Swasey, and consists, like the ordinary com- 

 parator, of a microscope moved by screws in 

 ordinates and abscissae, but this is here com- 

 bined with a cone and rolling disk. The disk 

 moves horizontally along the elements of the 

 cone as governed dii-ectly by the position of 

 the microscope in ordinates, while the num- 

 ber of revolutions of the cone is proportional 

 to the motion of the microscope in abscissae. 

 Accordingly the number of rotations of the 

 disk is proportional to products of ordinates 

 and abscissae, and by passing along the con- 

 tour of the curve between given abscissae, and 

 back over the zero line to the original starting 

 point, the difference in reading of the disk 

 counter yields the area. 



As constructed, the machine is best suited to 

 areas of more than ten square centimeters, 

 but a smaller machine would doubtless be 

 equally successful. The accuracy of meas- 

 urement actually reached with the instrument 

 shown is 0.1 square centimeter, and numerous 

 measurements of circles and other areas to 

 this degree of accuracy were cited. 



Mr. F. E. Fowle, Jr., also of the Smith- 

 sonian Observatory, then discussed ' The Dis- 

 crepancy between Solar-Constant Measures 

 by the Actinometer and by the Spcctro-Bolom- 

 eter.' He referred to Mr. Langley's proof that 

 actinometric extrapolation by Bouguer's for- 

 mula gives necessarily too low values for the 

 extra-atmospheric solar radiation. It is, how- 

 ever, found by comparison with spectro- 

 bolometric determinations that the discrep- 

 ancy is nearly constant and is about 14 per 

 cent, for such atmospheric conditions as exist 

 at Washington, when Angstrom's actinometer 

 is used. 



Further refinements to the correction may 

 later be determined as functions of the slope 

 of the actinometer curve, the humidity and 

 the air masses serving for the extrapolation. 



Charles K. Wead, 



Secretary. 



THE BIOLOGICAL SOCIETY OF WASHINGTON. 



The 395th regular meeting was held at the 

 Assembly Hall of the Cosmos Club on Jan- 

 uary 14, 1905, with President Knowlton in 

 the chair and forty-six persons present. 



Dr. A. D. Hopkins showed specimens of 

 what are undoubtedly fossil borings, probably 

 by some beetle of the family Cerambycidae. 



Professor W. P. Hay renewed a discussion 

 from a previous meeting, and stated that 

 proper credit is given in the scientific world 

 to Caesalpinus for the discovery of what we 

 commonly know as the circulation of the 

 blood. 



^Ir. C. O. Townsend presented a paper on 

 the ' Distribution and Development of the 

 Sugar Beet Industry,' in which he called at- 

 tention to the difference between the sugar 

 beet and the beet sugar industries. Of the 

 latter he illustrated by lantern slides some of 

 the largest beet sugar factories, the largest 

 being in southern California. He then showed 

 a very instructive series of slides dealing with 

 the sowing, cultivation, harvesting and ship- 

 ping of the sugar beet crop, including views 

 of the workers employed, machinery used and 

 results gained. 



Mr. A. C. Veatch discussed ' The Question 

 of Origin of the Natural Mounds of Louisi- 

 ana, Arkansas and Texas ' (illustrated with 

 photographs). Of the many theories of origin 

 suggested for these mounds three deserve the 

 most careful attention: (1) the spring and gas 

 vent theory, (2) the dune theory, and (3) the 

 ant hill theory. 



In the spring and gas vent theory it is 

 argued that the gas produced by the decay of 

 the large amount of vegetable matter buried 

 in the coastal plain strata has, with the ar- 

 tesian water associated with it, brought to the 

 surface fine sand and built up low cones. 

 Small cones are now forming in this manner 

 at many points in the coastal plain, and they 



