470 



SCIENCE 



[N. S. Vol. XXXIII. No. 847 



THE AMEEICAN PHILOSOPHICAL SOCIETY 



The Investigation of Explosives at the Pittsiurgh 

 Testing Station: Professor Charles E. Mun- 

 ROE, "Washington, D. C. 



The many and mcreasing nmnber of accidents 

 giving rise to serious casualties that have at- 

 tended the mining of coal has in recent years led 

 thoughtful men to inquire into the causes of such 

 accidents with a view to their prevention. Among 

 other causes, it was found that the improper use 

 of explosives, or the use of improper explosives 

 had often operated to produce these accidents, 

 and it appeared evident that here was a cause 

 that ought, by study of materials and methods, 

 to be remedied. This study was begun some years 

 ago, but it was much advanced when, following a 

 series of disasters in the fall of 1907, by which 

 623 men were killed, Congress appropriated money 

 for the investigation. A testing station was 

 opened at Pittsburgh in the following year, where 

 the explosives could be exploded, under known 

 conditions, in the presence of sensitive fire-damp 

 and of coal-dust laden air. A standard was fixed 

 upon which the explosive must satisfy. An ex- 

 plosive which passes the test is styled a "per- 

 missible" explosive and its name is published. 

 The list about to be published by the Bureau of 

 idines will contain the names of 69 permissible 

 explosives made by sixteen different American 

 manufacturers. These explosives are sometimes 

 styled "short flame" or "safety" explosives, 

 but the term "safety" is improper. According 

 to a canvass by the Bureau of Mines, 8,942,857 

 pounds of short-flame explosives were made in 

 1909. Professor Munroe, with the aid of lantern 

 slides, described the apparatus employed and its 

 method of use. 



THE BOTANICAL SOCIETT OP WASHINGTON 



The 70th regular meeting of the society was 

 held at the Cosmos Club, Tuesday, February 7, 

 1911, at 8 o'clock p.m. In the absence of both 

 president and vice-president Dr. W. H. Evans 

 was chosen chairman pro tem. Thirty-one mem- 

 bers were present. Dr. C. O. Appleman, E. G. 

 Boerner, Gr. N. Lamb, W. J. Morse, C. A. Eeed, 

 Wm. Shear, C. B. Smith, A. V. Steubenrauch and 

 Dr. W. Van Fleet were admitted to membership. 



The following papers were read: 



The Effect of Temperature on the Respiration 

 of Fruits: H. C. Gore. 



The rates of respiration were given of many 

 fruits at different temperatures. It was found 

 that the forty different fruits studied obeyed 

 approximately the same law in regard to the 

 effect of temperature. The rate of respiration 

 increased two to three times for each 10° C. rise, 

 following van't Hoff's rule for increase in rate 

 of chemical reactions with temperature. The res- 

 piratory activity of the different fruits varied 

 greatly and no correlation appeared between it 

 and composition or size. In general, fruits which 

 grow and mature rapidly and soon become over- 

 ripe, respired rapidly; while fruits having a long 

 growing season and maturing slowly were much 

 less active. 

 Collecting Grasses in Mexico: A. S. Hitchcock. 



Mr. Hitchcock described his recent trip to 

 Mexico for the purpose of collecting and studying 

 the grasses of that region. He gave considerable 

 attention m his paper, to the physiographic and 

 climatic conditions and the relation of these con- 

 ditions to the flora. Tables and maps were sub- 

 mitted showing the topography of the country, 

 and the monthly rainfall and temperature of 

 several representative stations. The speaker de- 

 scribed the floral regions, the distribution of the 

 grasses as affected by rainfall and altitude, and 

 reviewea briefly the agricultural and range con- 

 ditions, including the forage crops. The paper 

 was illustrated with about fifty lantern slides 

 from photographs taken by himself and his son. 

 Prank H. Hitchcock, who accompanied him as 

 assistant. 



The forty localities visited by Mr. Hitchcock 

 included many type localities, which led to the 

 rediscovery of certain little-known or doubtful 

 species of grasses described by earlier writers, 

 among which species may be mentioned Bouteloua 

 repens HBK., Panieum decolorans HBK., P. 

 buohingeri Fourn., P. cordovense Fourn. and P. 

 ichnanthoides Fourn. It is highly probable that 

 Mr. Hitchcock collected specimens from the same 

 group of plants from which the types of the last 

 two species were obtained. On the other hand, 

 species previously supposed to be restricted in 

 range were found to be widely distributed. Pani- 

 eum arieonicum Scribn. & Merr., known in Mexico 

 only from tne northwestern states, was collected 

 as far south as the state of Oaxaca. These facts 

 emphasize the point that, when possible, the spe- 

 cialist should make his own collections. 

 The Rediscovery of the Xochinacaztli of the 



Aztecs, with Notes on Mexican Anonacece: W. 



E. Safpoed. 



