148 Professor Denison Olmsted on the 



Tourmalines of Elba. In the Grand Duke's collection at 

 Florence there is a specimen 11 inches square, with four 

 erect green tourmalines and one prostrate, 2, 4, and 21 inches 

 long, and | to 1 inch thick. They are associated with ortho- 

 clase and crystallized quartz. The pink tourmalines of Elba 

 have always the basal plane OR, while the green prisms are 

 terminated with rhombohedral planes. 



Analcime? A singular analcime-like mineral occurs at 

 Monte Catini, in which the soda replaces the magnesia, ac- 

 cording to Professor Moneghini of Florence, who obtained 

 for its composition — 



Si Al Mg Na K H 



59-347 22-083 10-250 0-450 0-015 7*560 



[This result give the oxygen ratio for the protoxids, per- 

 oxids, silica, and water 1 : 2 : 6: 1|.] 



Observations on the Zodiacal Light ; with an Inquiry into its 

 Nature and Constitution, and its Relations to the Solar 

 System, By Denison Olmsted, Professor of Natural 

 Philosophy and Astronomy in Yale College.* With a 

 Plate. Read before the American Association for the Ad- 

 vancement of Science, at the Annual Meeting at Albany, 

 August 1851. 



I submit to the Association a series of observations on the 

 Zodiacal Light, made by me at Yale College from 1833 to 

 1839, upon the basis of which I propose to offer a new descrip- 

 tion of this mysterious phenomenon, and a brief inquiry into its 

 nature and constitution, and its relation to the solar system. 

 Particularly, I propose to inquire whether or not it is the 

 origin of the meteoric showers of November and August. 



Various circumstances conspire to interrupt the continuity 



* In next number of this Journal a particular account of the Zodiacal Light as 

 seen in Southern Africa will be given. 



