E. S. Dana—Mineralogical Notes. 139 



ingly, we repeated the described experiment with the following 

 modifications: The final flask, above mentioned, in which the 

 carbon monoxide and the ozone were brought together, was 

 replaced by two large glass balloons, and these were placed in the 

 direct light of the sun. Again slow currents of carbon monox- 

 ide and ozone were passed through the apparatus for hours, the 

 rapidity of the currents being varied at diflferent times. 



In this case also we obtained only a negative result. We 

 hence are in a position to assert positively that carbon monox- 

 ide is not oxidized by ozone. 



If we now bear in mind that ozone acts destructively upon a 

 great many saturated stable compounds, that one of the atoms 

 of the ozone molecule has a great ^tendency to unite with other 

 bodies, then the result of the above described experiments 

 remains inexplicable. It shows at nil events that carbon- 

 monoxide itself, at the ordinary temperature, has no very great 

 tendency to unite with oxygen, for, if our ideas in regard to the 

 nature of ozone are correct, the conditions for such union were 

 very favorable in our experiment. 



VVe hope gradually to be able to experiment more fully upon 

 this interesting subject with the object of collecting material 

 which may enable us better to understand the nature of the 

 so-called non-saturated compounds. We propose next to study 

 the action of hydrogen peroxide upon carbon monoxide. 



Art. XYl.—Minerahgical Notes ; by Edward S. Dana. — No. 

 I. On the Optical Character of the Chondrodite of ike Tilly 

 Foster Mine, Brewster, Neiv York. 



In a memoir on the Brewster chondrodite, published in the 

 third volume of the Transactions of the Connecticut Acad- 

 emy, I have given the results of an optical examination of 

 chondrodite crystals of the second type.* It was there shown 

 that the optic axes lie not in the basal plane, but in a plane 

 making an angle of about 154° 10' with the base; and, in con- 

 sequence, that the crystals of this type, at least from that local- 

 ity, belong optically not to the orthorhombic system, but to the 

 monoclinic, while the various measurements proved that the 

 deviation in angle from the orthorhombic type could not be 

 greater than 2 or 3 minutes. A recent repetition of the meas- 

 urements with the stauroscope on the same crystals, and also 

 on another not examined before, confirm the results ob- 

 * See also this Journal, III, ii, 63, for extracts from the paper. 



