Polytechnic Association Proceedings. 953 



this microscopic plant known as Aspergillus niger, and carefully 

 exclude the air. 



THE COLOR OF STARS. 



Mr. John Browning of the Royal Astronomical Society states 

 that colors of celestial bodies estimated by comparison with the 

 ingenious chromatic scale of Admiral Smyth, in which each color 

 is represented of four different degrees of intensity, will not possess 

 any relative value unless taken in connection with the aperture of 

 the telescope employed when the color was estimated. Experi- 

 menting in relation to this subject, he had noticed that the chocolate 

 color of the so-called belts of Jupiter is much more perceptible 

 with an object glass of six inches in diameter than with one twelve 

 inches. A small cluster in Perseus appears of an indigo blue with 

 eight and a half inches, Prussian blue with ten and a quarter inches, 

 and royal blue with tAvelve and a half inches of aperture. Were 

 due allowance made for this disturbing influence by variation of 

 aperture, many discrepancies between colors attributed to double 

 stars by different observers might probably be reconciled. 



THE LIGNITES OF THE WEST. 



Mr. F. V. Hayden, U. S. Geologist, has published, by permis- 

 sion, in The American Journal of Science and Arts, an abstract 

 from his forthcoming report of the United States Geological Survey 

 of Nebraska, which contains observations made by him during the 

 autumn of 1867, in regard to the lignite deposits of Colorado and 

 Dakotah. The following statements will be read with interest 

 by those who have raised the question concerning the supply of 

 fuel for the Union Pacific railroad: 



Mr. Hayden's examination of the geology of Nebraska having 

 failed to develop any workable beds of coal in that State, his atten- 

 tion was directed to the great lignite deposits of the Laramie plains. 

 He found the lignite to be of excellent quality, in beds from five 

 to eleven feet thick, and he estimated the area occupied by this 

 basin at five thousand square miles. Its most eastern limit is about 

 ten miles east of Rock creek, a branch of the Medicine Bow river. 

 Outcroppiugs have been seen all along Rock creek. Medicine Bow, 

 on Rattlesnake Hills, on the North Platte, Muddy creek, all along 

 Bitter creek. Ham's Fork, Echo Canon, and all along Weber river, 

 nearly to Great Salt Lake, showing that one connected series of 

 deposits covers this whole area. The lignite taken from the beds 

 on Rock creek is from the outcroppiugs, yet it burns with a bright 



