Mat 19, 1916] 



SCIENCE 



707 



fessor Frederic Palmer. Eesearches on the 

 photoelectric effect and on the reflection of 

 metals in the extreme ultra-violet are now 

 being conducted by Dr. Sabine and Dr. 

 Gardner. 



Professor Davis is chiefly occupied with 

 thermodynamics, his work on the thermal prop- 

 erties of steam being somewhat widely known 

 through Marks and Davis's " Steam Tables." 

 At the present time he and Mr. Kleinschmidt, 

 a research student, are setting up the neces- 

 sary apparatus for reproducing the interna- 

 tional temperature scale with great precision 

 by means of resistance thermometers, in the 

 hope of verifying and completing some work 

 of Professor Richard's along that line. Four 

 other students have carried on experimental 

 work under his direction; Dr. Trueblood on 

 the Joule-Thomson effect in superheated 

 steam. Dr. Komberg on the specific heat of 

 water, Mr. Eoyster on the Joule-Thomson 

 effect in thermometric gases, and Mr. Loomis 

 on the thermal properties of mercury vapor. 

 The first two of these researches are nearly 

 ready for publication; the last two are still in 

 progress. 



The work of Professor Bridgman is perhaps 

 as well known as that of any member of our 

 staff. I am indebted to him for the following 

 summary: The thermodynamic properties of 

 matter have been investigated under three 

 main headings. The first heading has to do 

 with the properties of liquids that do not 

 freeze up to 12,000 kg. The chief results were 

 these : nearly all the liquids show a reversal 

 of dilatation at high pressure, the dilatation 

 at the higher temperatures becoming less than 

 at lower temperatures. Beyond a certain pres- 

 sure, the repulsive forces between the mol- 

 ecules predominates over the attractive forces so 

 that work is stored up as pressure is increased. 

 All liquids show persistent individual varia- 

 tions, doubtless in some way connected with 

 specific molecular properties. The second 

 heading has to do with melting curves. By 

 examination of some 20 liquids, the character- 

 istics of their melting curves at high pressure 

 have been established; neither of the two 

 theories, formerly accepted as correct, is true. 



The melting curve neither ends in a critical 

 point nor passes through a maximimi, but con- 

 tinues to rise indefinitely, approaching a 

 straight line at high pressure. The third head- 

 ing has to do with polymorphic changes of 

 solids. Some 150 substances have been exam- 

 ined and the phase diagrams of 30 substances 

 have been studied and a number of new modi- 

 fications have been found. The relations are 

 most complicated and do not tend to any com- 

 mon type of behavior at high pressure. It is 

 the rule that the phase of smaller volume is 

 more compressible than the phase of greater 

 volume and there are a number of cases in 

 which the phase stable at higher pressures has 

 a smaller specific heat. It can be definitely 

 proved by these results that, at least in many 

 cases, the centers of attractive force between 

 the molecules are not located at their geo- 

 metrical centers, but are probably close to the 

 surface. 



Dr. Chaffee's chief interests lie in the same 

 field as those of Professor Pierce, but, as part 

 of his work is still carried on in this building, 

 it is fair to claim his study of oscillatory cir- 

 cuits as a product of this laboratory; as one 

 result of this investigation he has perfected 

 the " Chaffee Gap " a device of wide utility in 

 wireless telegraphy. 



Among the junior members of the teaching 

 staff. Dr. D. L. Webster has recently turned 

 his attention to the experimental study of 

 characteristic X radiation ; thanks to the gen- 

 erosity of the General Electric Company, and 

 by the use of the laboratory's 40,000-volt stor- 

 age battery, he has already obtained some im- 

 portant results from a rhodium target. Dr. 

 Clark has been at work on the study of the 

 vibrations in a stretched wire ; he is at present 

 engaged in the design and construction of a 

 deep-sea thermometer. Dr. !N"usbauni is en- 

 gaged upon the study of hysteresis loss in iron 

 at very high frequencies. 



There are in all twelve candidates for the 

 doctorate at present at work on pieces of re- 

 search or on theoretical problems; the fields 

 of study of five of these men have been already 

 mentioned; of the other seven, four are work- 

 ing in spectroscopy, a subject for which we are 



