TWENTY-FIRST YEAR OF PUBLICATION. 
AND ANNALS OF 
ASTRONOMY, BIOLOGY, GEOLOGY, INDUSTRIAL ARTS, 
MANUFACTURES, AND TECHNOLOGY. 
(MONTHLY, FORMERLY “THE QUARTERLY JOURNAL OF SCIENCE.”) 
Articles. page 
1. A Description of the Process 
of “Hydraulic Mining” in 
California, with Explanations 
concerning the Origination of 
Gold-bearing Alluvium there, 
and Elsewhere. By George 
O’Brien 44 i 
2. Observations on Twilight .. 4 5i 
3. On Eledricity and its Present 
Applications. By W. Fraser, 
A.M., M.R.C.S. Eng 456 
4. Emerald-green : its Properties 
and Manufacture. By Robt. 
Galloway, M.R.I.A 467 
5. Significant Nomenclature. By 
Wm. John Grey, F.C.S. .. 472 
Articles — continued. page 
6. Thoughts on Imitation. By 
J. W. SlaTer 475 
7. Observations of Bright Lines 
in the Spectra of Fixed Stars 480 
Analyses of Books. 
The Law of Sex 484 
Sleep-Walking and Hypnotism.. 487 
A Treatise on Earthy and other 
Minerals, and Mining .. .. 4.S9 
The Atheistic Platform .. .. 4 go 
Corpulence, and its Treatment 
on Physiological Principles . . 492 
&c., &c. 
Correspondence 
Notes 
497 
499 
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