II ADVERTISEMENT. 
li:5. Report of work done in the Division of Chemistry and Physics during the fiscal years 
L89] 92 and 1892-93, by F. W. Clarke. 1893. 115 pp. Price, 15 cents. 
111. Earthquakes in California in 1893, by Charles D. Perrine. 1894. 215 pp. Price, 5 cents. 
125. The constitution of the silicates, by Frank Wigglesworth Clarke. 1895. 100pp. Price,15 
cents. 
L29. Earthquakes in California in 1894, by Charles D. Perrine. 1895. 25 pp. Price, 5 cents. 
D7. Earthquakes in California in 1895, by Charles D. Perrine. 1896. 23 pp. Price, 5 cents. 
148. Analyses of rocks, with a chapter on analytical methods, laboratory of the United States 
Geological Survey, 1880 to 1896, by F. W. Clarke and W. F. Hillebrand. 1897. 300 pp. Price, 20 
cents. 
155. Earthquakes in California in 1896 and 1897, by Charles D. Perrine. 1898, 47 pp. Price, 5 
cents. 
161. Earthquakes in California in 1898, by Charles D. Perrine. 1899. 31 pp., 1 pi. Price, 5cents. 
107. Contributions to chemistry and mineralogy from the laboratory of the United States 
Geological Survey; Frank W. Clarke, Chief Chemist. 1900. 100 pp. Price, 15 cents. 
168. Analyses of rocks, laboratory of the United States Geological Survey, 1880 to 1899, tabu- 
lated by F. W. Clarke. 1900. 308 pp. Price, 20 cents. 
J 70. Some principles and methods of rock analysis, by W. F. Hillebrand. 1900. ID pp. Price, 
15 cents. 
180. On pyrite and marcasite, by H. N. Stokes. 1900. 50 pp. Price, 10 cents. 
