1892.] 



THE MICROSCOPE. 



143 



Volcanic Dusts. — The following volcanic dusts from the 

 Andes are being advertised as for sale in London at 37 cents per 

 bottle, containing about i grain each : 



1. Cotopaxi^ eruption of June 26, 1S77, which fell at Qiiito 

 after an aerial voyage of 34 miles. In the brown glass chips vac- 

 uoles are abundant; many of them range from about .001 to .002 

 inch in diameter, but some are still smaller. 



2. Cotopaxi^ eruption of July 3, 1S80, which was ejected to a 

 height of 40,000 feet above the level of the sea, and fell on Chim- 

 borazo after an aerial voyage of 64 miles. The finest particles 

 weigh less than one twenty-five thousandth part of a grain. 



3. The Tei'viinal Slope of Cotopaxi\ 19,^00 feet above the 

 level of the sea. This is the matter which is ejected daily by the 

 volcano. 



4. Pj'ovi ij.joo feet oil Cotopaxi^ about 2000 particles to a 

 grain. The granules commonly range from .01 to .015 inch in 

 diameter. The most abundant are minute lapilli of scoriaceous 

 aspect; in less numbers are glassy whitish and reddish granules — 

 with these occur fragments of felspar, augite, and hypersthene. 



5. Lapilli fro 7Ji i^^ooo feet on Cotopaxi. Pumiceous lapilli, 

 pulverized glass, and mineral fragments. 



6. Lapilli from Aiuhato {8600 feet). Mainly colorless, vesic- 

 ular pumice. Many of the fragments have entangled within them 

 small microliths, and also 2:>lates of a pale greenish mica. The 

 town of Ambato is built upon this deposit. 



7. F'rom Machachi {gSoo feet)., existing as a continuous 

 stratum ten Inches thick, the product of some unrecorded eruption 

 of great intensity. Consists largely of felspar and hornblende. 

 The finest particles are felspar and pumice. 



S. Fine Pumice Diist from Mac/iac/ii {gSoo feet) . This 

 forms beds many feet In thickness, and consists mainly of clear, 

 colorless, vesicular pumice, which Includes greenish mica, some 

 in minute hexagonal plates. 



PVBLICATIONS 



Education and Culture as related to the Health and Diseases 

 of Women. By A. J. C. Skene, M. D. Detroit: Geo. S. 

 Davis. i6mo, pp. 167. 

 This is a little book that can be read through at a single sitting, 



