620 



SCIENCE 



[N. S. Vol. XXXIII. No. 851 



The ball, the earth and the moon are por- 

 tions of matter, one of the fundamental enti- 

 ties, or primary concepts (defining concept as 

 that of which the mind thinks, and not an 

 action of the mind). Gravitational attrac- 

 tion, a force, whether a push or a pull, is 

 also a fundamental entity. Energy, velocity, 

 work, etc., are complex concepts, or mathe- 

 matical expressions, involving two or more 

 simple concepts, such as, matter, space, time 

 and force, besides the concepts of condition, 

 such as direction, relative position and avail- 

 ability. The potential energy of the ball on 

 the shelf is not merely five foot-pounds, it is 

 five foot-pounds relative to the position of the 

 floor, and it is not available until it is rolled 

 off the shelf. 



Consider a one-pound ball held in the hand 

 five feet above the floor of a railroad car 

 which is traveling eastward at the rate of 

 32 feet per second. It has 5 foot-pounds of 

 potential energy and zero kinetic energy rela- 

 tive to the floor of the car, and JMV^^16 

 foot-pounds of kinetic energy relative to the 

 earth. If it is thrown westward at the same 

 velocity that the car is moving eastward, it 

 has zero velocity and zero kinetic energy rela- 

 tive to the earth, but 16 foot-pounds of kinetic 

 energy relative to the car, and it is capable 

 of breaking the window in the door of the car 

 if thrown against it. 



If Dr. Brush's kinetic theory of gravitation 

 depends on the hypothesis that the potential 

 energy of a body raised from the earth's sur- 

 face and held by the attraction of the moon 

 (or of a magnet) disappears entirely and be- 

 comes resident in the ether, it is not likely to 

 meet with acceptance. 



There seems to be another weak point in his 

 theory, viz., he assumes that the long radiant 

 waves of ether, the hypothetical cause of 

 gravitation, " pass freely through all bodies," 

 and yet that they east a " shadow." These 

 two ideas seem to be inconsistent. A perfectly 

 transparent glass plate casts no shadow of 

 light when rays of light pass freely through it. 



William Kent 



MONTCLAIE, N. J., 

 April 3, 1911 



WHAT IS THE GENOTYPE OF X-US JONES, 1900, 

 BASED UPON A SPECIES ERRONEOUSLY DETER- 

 MINED AS ALBUS SMITH, 1890? 



Statement of Case. — Jones proposes the new 

 genus X-us, 1900, type species alius Smith, 

 1890. 



It later develops that alius Smith, 1890, as 

 determined by Jones, 1900, is an erroneous 

 determination. 



What is the genotype of X-us, 1900; alius 

 Smith, 1890, or the form erroneously identi- 

 fied by Jones as alius in 1900? 



Discussion. — The nomenclatorial problem 

 expressed in the caption of this note is solved 

 in two diametrically opposite ways by differ- 

 ent authors. 



Some writers maintain that the original 

 alius Smith, 1890, is the genotype, while 

 others maintain that the genotype is repre- 

 sented by the species actually studied by 

 Jones and misdetermined as alius Smith. 



Cases of this general nature have given 

 rise to considerable confusion in nomencla- 

 ture, and several such cases have been referred 

 to the International Commission on Nomen- 

 clature for opinion. 



At the last meeting of the commission, the 

 principles involved came up for discussion, 

 but it was impossible to reach a unanimous 

 agreement. On account of the differences of 

 opinion, the secretary was instructed to make 

 a careful study of a number of cases, and to 

 report upon the same to the commission. 



It is not difficult to foresee that no matter 

 how the cases are finally decided, great dis- 

 satisfaction will arise among zoologists be- 

 cause the opinion rendered is not the direct 

 opposite of what it eventually will be. 



Recognizing that this is one of the most 

 difficult cases that has ever been submitted to 

 the commission, and recognizing the fact that 

 regardless of our action we shall probably be 

 criticized more on basis of our decision on 

 this case than because of any other opinion 

 that we have rendered, I am desirous of study- 

 ing at least one hundred cases if possible, that 



