MISCELLANY. 



637 



crevice are seldom discolored more than an 

 inch in depth, and the mineral adheres but 

 slightly. 



The dry dust of the mine is very in- 

 flammable, and two accidents from explo- 

 sion have occurred. The asphalt contains 

 about 76 per cent, of carbon, and yields 

 about 100 gallons of oil per ton. 



Agassiz's Successor. — It is rare that the 

 mantle of the father sits worthily on the 

 son. Especially is this true when the father 

 has been signally eminent in pure science. 

 Happily, indeed, is it for America, and for 

 biological science, that the vast plans of the 

 late Agassiz are to be continued, as far as 

 possible, on the grand scale upon which his 

 great mind projected them. The worthy 

 successor of Prof. Agassiz is his son Alex- 

 ander, whose name, in zoological investiga- 

 tion, is already acknowledged as a bright 

 light in the Old World and the New. One 

 of the most thoroughly worked-out mono- 

 graphs, so far as it is carried, and the most 

 sumptuously gotten up, is the one recently 

 published by Mr. Alexander Agassiz, con- 

 taining his researches and memoirs on the 

 Echinoderms, and which won for him the 

 first award of the Walker prize of $1,000, 

 by the Boston Society of Natural History. 

 Mr. Alexander Agassiz is to succeed his 

 father in the conduct of the Penikese Nor- 

 mal School of Natural History. That great 

 institution, the pride of Massachusetts, and 

 the envy of the savants of the Old World, 

 " The Museum of Comparative Zoology," at 

 Cambridge, Mass., has been placed under 

 the direction of Alexander Agassiz and Mr. 

 Cary, " both of whom are thoroughly con- 

 versant with Prof. Agassiz's plans with re- 

 gard to the museum, and familiar with the 

 collections." Thus, while all must lament, 

 as a great loss, the demise of that wonder- 

 ful man, yet a deep solicitude has been re- 

 moved from many minds as to the fate of 

 the professor's plans. 



Lime-Soils and the Potato-Rot. — A writer 

 in the Chemical News is led, by analysis of 

 diseased and sound potato - tubers, to as- 

 cribe the potato-rot to a deficiency of lime 

 and magnesia in the soil. Different observ- 

 ers state the percentage of magnesia in the 

 ash of sound tubers at from five to ten per 



cent. ; in the diseased tubers analyzed by 

 the author it was only 3.94 per cent. Anal- 

 ysis of sound tubers shows over five per 

 cent, of lime, but in the ash of diseased tu- 

 bers the author found only 1.77 per cent. 

 A similar observation was made some years 

 ago by Prof. Thorpe with regard to dis- 

 eased and healthy orange-trees ; in the for- 

 mer there was a deficiency of lime and mag- 

 nesia. 



It was shown, by the late Dr. Crace 

 Calvert, that lime is one of the few known 

 substances that are capable of altogether 

 preventing the development of fungi in or- 

 ganic solutions. He does not give any ex- 

 periments relating to the action of caustic 

 magnesia on fungi ; but doubtless that ac- 

 tion will be found to be similar. 



" Here, then," observes the author, " is 

 a curious and significant fact. Diseased po- 

 tatoes are deficient in lime-salts, and lime 

 prevents the development of fungi. May 

 not the development of fungi in the vessels 

 of plants be furthered by this deficiency ? 

 The circumstances are such as scarcely to 

 leave room for doubt. So far, then, theory 

 and practice agree : lime has been found by 

 experience to be useful in preventing the 

 disease, and it is likely that magnesia will 

 be found to have a similar effect." 



Clay Wasp-Nests. — All the American spe- 

 cies belonging to the genus Polistes (wasps) 

 have been considered paper-nest builders ; 

 but P. R. Uhler, at the Portland meeting of 

 the American Association, described a spe- 

 cies which build nests of clay. This wasp 

 is of dark-brown color, with yellow bands 

 across the abdomen, and with yellow feet. 

 The insect builds a nest of cylindrical shape ; 

 and a number of these cylinders were found 

 in the stump of a decayed tree, in Charles 

 County, Md. The central cavity of the 

 stump — which was about five inches in di- 

 ameter — contained thirty-three of these pe- 

 culiar structures. They were of yellow 

 clay, generally about half an inch in diame- 

 ter, and varying from two to five inches in 

 length. 



The nest, or more properly the recep- 

 tacle for the egg and young, is constructed 

 in the following manner : The adult wasp 

 works some wet clay into an oval pellet, 

 and carries it to the place where the nest is 



