142 CARNEGIE INSTITUTION OF WASHINGTON. 



for the purpose of increasing our knowledge of the relations of fumarole 

 gases to the original volcanic gases of the same region. The results follow: 



HjO 96..'. 



Fixed gases (CO2, etc.) 3.6 



SO2 096 



Ss 004 



HCl trace 



100.00 



Instead of attempting to determine the amount of each constituent in a 

 measured amount of fumarole gas, the ratios of steam to (1) fixed gases, (2) 

 sulphur vapor, (3) sulphur dioxide were separately determined. The volume 

 of each constituent in the gaseous state at the temperature (and correspond- 

 ing pressure) of the fumarole gases was then calculated. The temperature and 

 pressure in this case were 95.5° and 646 mm. The steam was always measured 

 as condensed water. The fixed gas was measured by water displacement in 

 an aspirator, while a sample of it was collected by a special tube in the train. 

 The free sulphur was condensed along with the water from which it was later 

 separated by filtration, after which it was dried and weighed. The sulphur 

 dioxide was collected by absorption in caustic soda. It was then oxidized 

 to sulphate by hydrogen peroxide, precipitated as barium sulphate, and 

 weighed. The amount of thie precipitate due to free sulphur was of course 

 subtracted. The methods proved practical and the results were very satis- 

 factory. 



(497) Cubanite: Identity with chalmersite; magnetic properties. H. E. Merwin, R. H. 



Lombard, and E. T. Allen. Am. Mineralogist, 8, 135-138. 1923. 



Cubanite, as described from such typical localities as southeastern Cuba, 

 also Tunaberg and Kafveltorp in Sweden, is compared with chalmersite from 

 Brazil and Alaska. In all respects in which these minerals have been ade- 

 quately described they are identical. Cubanite is the older name. Cubanite 

 is unique among known strongly magnetic substances in having only one axis 

 of high magnetic susceptibility. 



(498) Petrology of the Hawaiian Islands: II. Hualalai and Mauna Loa. Henry S. Wash- 



ington. Am. J. Sci., 6, 100-126. 1923. 



In this paper, which is a continuation of No. 491, are described the lavas of 

 the two volcanoes, with 17 new analyses. The lavas of Hualalai are basalts 

 of rather uniform character, whereas those of Mauna Loa are referred to three 

 chief types of basalt, labradorite basalt, olivine basalt, and picrite basalt. 

 Most of the modern flows are of the first type, which contains an excess amount 

 of silica. Descriptions of the earliest known flows of Mauna Loa, with 4 

 analyses by Bailey, are incorporated ; these descriptions are taken from an as 

 yet unpublished report by W. O. Clark and F. L. Noble. These earliest 

 lavas belong to the same three types as do the later flows, and they seem to 

 have appeared in quite regular succession. 



(499) Methods for distinguishing natural from cultivated pearls. F. E. Wright. J. Wash. 



Acad. Sci., 13, 282-287. 1923. 



In recent years the Japanese have perfected a method of inducing pearl 

 oysters to grow pearls which are spherical in shape and so similar to fine 

 pearls in external appearance that pearl experts have had difficulty in dis- 

 tinguishing between them. The essential difference is that the cultivated 

 pearl contains, as nucleus, a bead of mother-of-pearl on which concentric 

 layers of nacre or pearly substance are deposited, whereas most fine pearls 

 consist of nacre throughout. Methods suitable for detecting the mother-of- 

 pearl nucleus in the cultivated pearl are the following: (a) Place the pearl 



