OCTOBEB 8, 1909] 



SCIENCE 



491 



diseases ") ; and Metcalf and Collins's " Pres- 

 ent Status of the Chestnut Bark Disease " (due 

 to Diaporthe parasitica, which thus far has 

 baffled all attempts at control, by anything 

 less than the destruction of the diseased trees). 



In Dr. Clinton's " Eeport of the Station 

 Botanist " (Conn. Agricul. Expt. Station, 

 1908) he takes a more hopeful view of the 

 future of the chestnut bark disease, believing 

 that the trouble is largely due to " winter in- 

 jury " rather than to the fungus above named, 

 and that it " is now probably about at the 

 height of its development, so that not much 

 additional harm may be expected." Another 

 paper in the same report takes up another 

 puzzling disease, peach yellows — and here, 

 also, a suggestion is made as to its nature 

 which at least has the merit of some proba- 

 bility. The closing paper gives the results of 

 artificial cultures of Phytophthora of different 

 species. This will be most useful to mycolo- 

 gists who may wish to introduce this method 

 of study in their laboratories. 



Other papers which may be mentioned here 

 are Professor DeLoach's " Studies on the Ool- 

 letotrichum gossypii " (Bull. 85, Georgia Expt. 

 Station) ; W. T. Home's " Eeport of the De- 

 partment of Vegetable Pathology " in the re- 

 port of the Estacion Central Agronomica of 

 Cuba (1905-09), and an earlier one by the 

 same author devoted to coconut diseases (Bull. 

 15) ; Freeman and Johnson's " Loose Smuts 

 of Barley and Wheat " (Bull. 152, Bureau of 

 Plant Industry) ; C. W. Edgerton's " Perfect 

 Stage of the Cotton Anthracnose " (Mycologia, 

 May, 1909) ; the same author's " Anthracnose 

 or Pod Spot of Beans " (Bull. 116, La. Expt. 

 Sta.) ; J. G. Grossenbacher's " Mycosphaerella 

 Wilt of Melons " (Tech. Bull. 9, N. Y. Expt. 

 Sta.) ; and G. W. Wilson's " Notes on Perono- 

 sporales for 1907 " (Bull. Upper Iowa Univer- 

 sity, XL, 3). 



We have space for only brief mention of 

 the following, also : Century XXIX. of "Fungi 

 Columbiani " (Elam Bartholomew, Stockton, 

 Kans.) devoted whoUy to fungi collected in 

 Arkansas ; Fawcett's " Fungi Parasitic upon 

 Aleyrodes citri " (Special Studies, 1; Univ. 

 Florida), with six plates; Rorer's "Bacterial 

 Disease of the Peach " (Mycologia, January, 



1909) ; Edwards and Barlow's " Legume Bac- 

 teria " (Bull. 169, Ontario Agricul. Coll.). 

 Charles E. Bessey 

 The UNnfEEsiTT of Nebbaska 



SPECIAL ARTICLES 



THE CONSERVATION OF MASS AND THE PASSING 

 OF MATTER 



To THE Editor of Science: The article by 

 Professor Lewis in the Technology Quarterly, 

 discussed in your issue of April 23, 1909, by 

 Professor Speyers, is one answer to the obvi- 

 ous necessity for an enlargement and restate- 

 ment of some of the fundamental concepts of 

 physics. 



The discovery of radioactivity by M. Henri 

 Becquerel, and that of polonium by Mme. 

 Curie, initiating us into the knowledge of a 

 new order of phenomena, together with the 

 observation by P. Curie and Laborde of a 

 continual production of heat by radium, and 

 the splendid experiment of Kaufmann on the 

 variation of mass with velocity, finally the 

 suggestion by Eutherford and Soddy that the 

 atoms of the radio-elements disintegrate with 

 production of helium, confirmed in the face of 

 great difficulties by Sir William Eamsay and 

 Mr. Soddy, have placed before us an array of 

 new facts for which new doctrines are im- 

 peratively needed. 



We may recall that the investigations of 

 Larmor, J. J. Thomson, Hicks and others, 

 exhibit to us a conception of an atom as a 

 world in miniature, where internal revolutions 

 and reactions of distinct internal entities at 

 enormous speeds give a basis for the discussion 

 of latent energies implied by the physical fact 

 of the inertia of the atom. 



That the mass of a body is nothing but the 

 energy of its ethereal rotation is a view which 

 I have held tentatively. Following the equa- 

 tions used by Professor Lewis, and introducing 

 this further premise, let il/ = momentum, 

 M' = Mr = angular momentum, or " moment 

 of momentum," of the ether, where r is the 

 radius of gyration of the reciprocating rota- 

 tions of the ether. The complex of these in- 

 tegrated rotations constitutes an electromag- 

 netic wave whose amplitude diminishes with 

 r as the spherical wave-front expands. Let 



