March 25, 1909] 



NATURE 



Absolute Measurement of Sound. 

 Dr. A. G. Webster announces the approaching com- 

 pletion of his research on the measurement of sound, which 

 has been in progress for two years past. The investiga- 

 tion comprises an exhaustive treatment of the tlieory of 

 the production of sound, with a description of a standard 

 source, the transmission of sound through the air as 

 modified by the effect of the ground, and its measurement 

 by a receiving instrument. A description of experiments 

 confirming the theory of Dr. Webster viJill be included in 

 his finished report, with several practical applications, such 

 as the examination of the sounds of speech, the diagnosis 

 of deafness, the improvement of fog signals, and the test- 

 ing of materials for the insulation of sound. 



Re-calctdatton of Atomic Weights. 

 In February, 1908, Prof. F. W. Clarke, chairman of the 

 International Commission on Atomic Weights, was 

 authorised to begin the preparation of a third edition of 

 his work on that subject, with the aid of a grant from the 

 Smithsonian Institution. The second edition of Prof. 

 Clarke's " .Atomic Weights " was published in 1897, since 

 which time the data on this subject have so largely in- 

 creased as to render a new edition desirable. Some time 

 will necessarily elapse before the completion of the work. 



Properties of Matter at Temperature of Liq^uid Air. 

 In October, 1907, a Smithsonian grant was approved on 

 behalf of Prof. E. L. Nichols, of Cornell University, for 

 the continuation of his experiments on the properties of 

 matter at the temperature of liquid air. Reports of the 

 progress of this research are to be made from time to 

 time in the recognised journals of physics, and, at the 

 completion of the research, a memoir describing the in- 

 vestigation will be submitted to the Smithsonian Institu- 

 tion for consideration as to publication. It is believed that 

 the prompt announcement of results in the way mentioned 

 will be an immediate advantage to students, and that their 

 publication as a whole by the institution will also prove 

 of great service. 



Flow of Air at High Pressure through a Nozzle. 



The inquiry to determine the cooling effect of the nozzle 

 expansion of air for large pressure differences, which has 

 been conducted by Prof. W. P. Bradley, of Wesleyan 

 University, with the aid of a grant from the Hodgkins 

 fund of the institution, is announced as nearing comple- 

 tion. The investigation was intended specifically to deter- 

 mine whether the cooling process is due to the Joule- 

 Thomson effect or to the performance of external work by 

 the expanding air in pushing back the atmosphere from 

 before -the nozzle. The results of the inquiry make it 

 clear that pressure is an important factor, and that the 

 cooling effect increases very rapidly indeed as the initial 

 teiTiperatirre falls. Prof. Bradley is now engaged in an 

 exact mathematical discussion of this research. 



As to the apparatus employed, an interchanger of the 

 Hampton type was so constructed, in vertical sections, that 

 the amount of interchanger surface in actual use could 

 be varied at -will, from nothing to more than enough to 

 •induce liquefaction. In this manner it was possible to 

 maintain the- initial temperature constant, within one-third 

 of a degree, at any desired point between +20° and 

 — 120°, and the final temperature similarly constant between 

 + 20° and lihe temperature of liquefaction. The tempera- 

 tures were measured by resistance thermometers placed 

 close to the valves in the high- and low-pressure circuits. 

 The pressures employed range from 500 lb. to 3000 lb. 

 The expansion was exclusively to one atmosphere. 



The inquiry is of interest as related to the functioning 

 of air liquefiers in which the air is throttled by a valve 

 and expands without performing external work, in the 

 usual sense of that expression. 



Study of the Upper Atmosphere. 

 A further grant from the Hodgkins fund was m.ide to 

 Prof. A. Lawrence Rotch, director of the Blue Hill Meteor- 

 ological Observatory, to aid in the completion of his ex- 

 periments with ballons-sondes at St. Louis. This was 



SO. 2056, VOL. So] 



accomplished in October and November, 1907, under the 

 direction of Mr. S. P. F'ergusson. 



The object of' these latest ascensions, twenty-one in 

 number, was to supply data for the high atmosphere 

 during the autumn, a season when there are few observa- 

 tions, and also to establish a comparison with the results 

 obtained simultaneously in Europe on the international 

 term days in October and November. Prof. Rotch reports 

 that all but two of the instruments used in these ascensions 

 were recovered, and an examination of the record sheets 

 indicates generally the presence, at an altitude exceeding 

 eight miles, of the isothermal, or relatively warm stratum, 

 which was found somewhat lower in summer. For 

 example, on October 8 the minimum temperature of 90° F. 

 below zero was found at a height of 47,600 feet, whereas 

 at the extreme altitude reached, namely, 54,100 feet, tlie 

 temperature had risen to 72° F. below zero. Similarly, on 

 October 10 the lowest temperature of 80° F. below zero 

 occurred at 39,700 feet, while 69° F. below zero was re- 

 corded at 49,200 feet, the limit of this ascension, showing 

 that the temperature inversion had come down about 8000 

 feet in two davs. 



The prevailing drift of the balloons during the autumn 

 of 1907 was from the north-west, while in previous years 

 they travelled more from the west. A description of the 

 methods employed in launching seventy-seven ballons- 

 sondes from St. Louis, and a discussion of the results 

 obtained, will soon appear in the Annals of the .Astro- 

 nomical Observatory of Harvard College. 



Air Sacs of the Pigeon. 



For several years there have been in progress under the 

 general direction of Prof, von Lendenfeld, of the University 

 of Prague, aided by grants from the Hodgkins fund, 

 various investigations bearing upon animal flight. The 

 results of one of these investigations, on the air sacs of 

 the pigeon, by Bruno Miiller, was published during the 

 past year in the Smithsonian Miscellaneous Collections. 

 The author summarises the conclusions of his studies as 

 follows : — ■ 



I do not consider the air sacs, including the air cavi- 

 ties of bones, as organs having a positive and special func- 

 tion, but rather as a system of empty interspaces. Jheir 

 value lies in their emptiness — that is, in their containing 

 nothing that offers resistance or has an appreciable 

 weight. 



Flying is the highest form of locomotion, and as such 

 only possible to a body of high mechanical efficiency. Our 

 most effective machines are by no means compact and 

 solid, but composed of parts as strong as possible in them- 

 selves and arranged in the most appropriate manner. The 

 interspaces between the parts are left empty and taken up 

 by air. 



The Sauropsida, at the time they obtained the power of 

 flight, became adapted to its mechanical requirements, and 

 thereby similar to the efficient machines mentioned above ; 

 they divested themselves of all superfluous material, filling 

 the body spaces thus obtained with air sacs. While the 

 body wallj adapting itself to the mechanical requirement, 

 became a compact, hollow cylinder serving as a support 

 for the organs of movement, the mobility of the parts was 

 assured by surrounding them with air sacs. 



The lengthening of the neck, produced by quite a 

 different adaptation, made necessary an increase in the 

 quantity of air moved during respiration. This demand 

 was met by air currents generated through a rhythmical 

 change in the volume of the air sacs. The connection of 

 the air sacs with the lungs is a consequence of their phylo- 

 genetic development, which is repeated in their embryo- 

 logical development, and has no physiological significance 

 other than that the air sacs assist in renewing the air 

 in the trachea. 



Preservation of Archaeological Sites. 



.Attention has been directed previously to what had been 

 done toward the preservation of archaeological objects on 

 the public domain from destruction by vandals and relic 

 hunters, and toward making these antiquities accessible 

 under proper rules and regulations. Under the terms of 

 an .Act of Congress approved June 8, 1906, uniform regu- 



