Chemistry and Physics. 367 



and the size of the striking body or plunger, which would indicate 

 that the latter acted as a resonator in compressural vibration, 

 taking up the vibrations started by the rubbing grains. In cups 

 of other materials, such as a paste-board box, a flower pot, or a 

 rubber vessel, the sand was mute. Although this point was not 

 mentioned it might be surmised that the porcelain was most suit- 

 able because its glazed surface more nearly approximated that 

 of quartz than the other surfaces. 



The author has no theory to offer in explanation of the origin 

 of the note in the motion of desert sands and it is difficult to see 

 how the granules should possess a period of vibration slow enough 

 to account for the pitch of the sound observed. 



A possible explanation mav be found in the idea suggested by 

 Osborne Reynolds {Phil Mag. 20, 469, 1885) that a mass of 

 grains in coming to rest will take up an arrangement of minimum 

 volume. When, however, they are disturbed the group may pass 

 through mau}^ successive minima of volume and if these minima 

 occur at approximately constant intervals of time the accompany- 

 ing change of volume might conceivablj^ transmit a periodic com- 

 pression to the surrounding air and thus produce a musical 

 sound. — Discovery 5, 156, 1920. 



6. The Electric Furnace: bv Henri Moissan. Pp. xvi, 313. 

 Easton, Pa., 1920 (The Chemical Publishing Co.).— This is a 

 second edition of the translation of the author's Le Four Elec- 

 irique, Paris, 1897, the first edition having appeared in 1904. 

 No attempt has been made to add in any way to the text of the 

 original French edition. The work is divided into four rather 

 long chapters which deal respectivelj^ with the description of 

 Different Models of Furnaces, the Various Modifications of Car- 

 bon, the preparation of ten Elements in the Electric Furnace such 

 as chromium, manganese, tungsten, vanadium, silicon, aluminum, 

 etc.. and finally with the preparation of Carbides. Silicides, 

 Borides, Phosphides, Arsenides, and Sulphides. 



The work of Moissan is too well known to call for any review. 

 It is the purpose of the publishers to make these classic researches 

 available for all who may wish them. The illustrations of the 

 French text have been reproduced in a manner which may be 

 sufficient for the purpose but nevertheless with the loss of all the 

 artistic value of the originals. 



7. Lessons in Heat; by AVilliam S. Franklin and Barry 

 MacNutt. Pp. xi, 147. Bethlehem, Pa., 1920 (Franklin and 

 Charles). — This is the third volume of the authors' Lesson Series. 

 The philosopliical ideas which underlie the Theory of Heat, such 

 as temperature, quantity of heat, and entropy,' are admittedly 

 difficult to grasp and to formulate. The authors' main effort has 

 been to connect up actual things and conditions with the mathe- 

 matical symbols and this attempt to state the physical essence of 

 thermodynamic principles has been commendably successful. 

 The six chapters take up in succession Thermometry, Calorimetry. 

 Changes of State, Heat Transfer, Properties of Gases and the 



