796 



SCIENCE 



[N. S. Vol. XXIX. No. 750 



substitute for lignum vitae in tke heartwood 

 of Xanthostemon verdugonianus, which weighs 

 7Y pounds per cubic foot. The tree is large, 

 with a diameter of 45 inches, and a length of 

 stem of 25 to 30 feet. It occurs in the 

 southern islands of the archipelago. 



Charles E. Bessey 

 University of Nebraska 



SPECIAL ARTICLES 



A FOSSIL GAR-PIKE FROai UTAH 



Some time ago Professor E. D. George ob- 

 tained in Utah a fine specimen of Lepisosteus 

 preserved in a block of limestone. The fossil 

 is of particular interest because the stone is 

 being quarried by the Western Lithographic 

 Stone Company, yielding slabs highly service- 

 able for lithographic purposes. The age of the 

 formation had not been determined until the 

 fish was examined, but it is now safe to say 

 that it is Middle or Lower Eocene. The 

 specimen was obtained twelve feet from the 

 surface, three miles northwest of Tucker, 

 Utah. It lacks the head, but is otherwise in 

 very good condition. In all respects, it agrees 

 excellently with Lepisosteus simplex Leidy, 

 as described and figured by Eastman.' East- 

 man's excellent figure, except for having the 

 head, might ahnost have been taken from our 

 specimen. The smooth scales, with occasional 

 minute pits, are in exact agreement, as are the 

 characters of the fins, etc. 



L. simplex was found in the typical Green 

 River locality in Wyoming, according to East- 

 man, though Hay ascribes it to the Bridger 

 Eocene. There is a species described from 

 Utah, L. cuneatiis (Cope), which lias smooth 

 scales, and it is at least very much like L. 

 simplex. This L. cuneatus comes from the 

 Manti shales, Manti being some fifty miles 

 south-southwest of Tucker. Eastman {loc. 

 cit.) ascribes this to the Miocene, but Cope 

 considered it Eocene, and it has been held that 

 the Manti shales are of the same age as the 

 Green River. It may be that the true Green 

 River extends from Wyoming to central Utah, 

 and that L. cuneatus is the same as L. sim- 

 plex. 



t. d. a. gookerell 



Univeesitt of Coloeado 



' Bull. Mus. Comp. Zool. XXXVI., No. 3. 



THE NUCLEATION OF A CLOSE LECTURE ROOM 



Recently, at the request of Professor Barus, 

 I made a series of measurements on the nuclei 

 in the air of a crowded lecture room. There 

 were over a hundred students in attendance 

 and the ventilation was not sufficiently brisk 

 to obviate the occurrence of somewhat of- 

 fensive closeness at the end of the hour. The 

 object of the investigation was to determine 

 whether any solid or liquid nuclei were 

 thrown off by the many lungs in action, 

 sufficient to be detected by the coronas of the 

 fog chamber in the presence of the natural 

 nucleation (largely inorganic) of the lecture 



i6 



84- 



-(8 



The method of investigation consisted in 

 aspirating the air of the room continuously 

 through the fog chamber and examining it by 

 exhaustion from time to time. The result 

 may best be given graphically by laying ofi 

 the nuclei in thousands per cubic centimeter 

 in a way to show their variation in the lapse of 

 minutes of time. 



The figure begins with a moderate measure 

 of dust during the desultory entry of the 

 members of the class. But throughout the 

 lecture hour the nucleation diminishes. Evi- 

 dently there is subsidence of dust (in part into 

 the lungs of the students who virtually cush- 

 ion the floor), but no corresponding evolution 

 of nuclei as resulting from the respiration of 

 this animated carpet. At the close of the lec- 

 ture, when the class rises hilariously as a body 

 to depart from the place of torment, they liter- 

 ally raise the dust again, in much larger 

 quantity than on entering. 



Unfortunately it is impossible to separate 

 the organic from the inorganic dust content of 

 this atmosphere for the present purposes. The 

 only conclusion attainable is, therefore, that 

 there is no appreciable evolution of non-gase- 

 ous matter, but rather an absorption of nuclei 



