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27. HOFFMAN.—Manual of Chemical Analysis as Ap¬ 
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for the Detection of Impurities and Adulterations. By 
Frederick Hoffman, Ph. D. 8 vo, cloth, illustrated. New 
York, 1873 .. 3 00 
28. JENKINS.—Electricity and Magnetism. By Flem¬ 
ming Jenkins. 12mo, cloth. London, 1873 . . . 1 50 
29. LOCKYER.—Contributions to Solar Physics. By 
J. N. Lockyer. Royal 8 vo, cloth. London, 1874 . . 7 50 
30. PIiYMPTON.—The Blowpipe. A Guide to its use in 
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various sources by Prof. Geo. W. Plympton, A. M. 12mo, 
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31. ROSCOE.—Lessons in Elementary Chemistry, In¬ 
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32. ROSCOE.—Spectrum Analysis. Six Lectures delivered 
in 1868 before the Society of Apothecaries of London. By 
Henry E. Roscoe, with Appendixes, Colored Plates and 
Illustrations. 3rd edition. 1 vol., royal 8 vo, cloth. Lon¬ 
don, 1872 . 9 00 
33. SOMERVILLE.—On the Conversion of the Physi¬ 
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1 vol., 12mo, cloth. London, 1858 . 4 50 
34. TYNDALL.—Sound: a Course of Eight Lectures deliv¬ 
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1877 . 2 00 
35. TYNDALL.—Notes of a course of Seven Lectures 
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36. TYNDALL.—Light and Electricity. Notes of two 
courses of Lectures. By John Tyndall. 12 mo, cloth. 
New York, 1871 ......... 1 25 
37. TYNDALL. — Researches on Diamagnetism and 
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magnetic Polarity. By John Tyndall. 1 vol., 8vo, cloth, 
with numerous Illustrations. London, 1870 . . . 7 00 
17. Insect Hunter’s Companion. A handbook for Insect 
collectors, Lepidoptera and Coleoptera. 12mo ... 75 
18. ALLEN, J. A.—Foray of a Colony of Formica San- 
guinea upon a colony of Black Ants, 1868 ... 10 
