ECONOMICAL CONSIDERATIONS. 567 
this mineral were noticed by Mr. Wadsworth in the washings from Morris 
Ravine. If present at all, it must be of quite rare occurrence. Zircon, on the 
other hand, has been frequently met with; the crystals are always minute. 
On the whole, the paucity of gems or other minerals in the gold washings of 
California is rather remarkable, as compared with their abundance in other 
parts of the world. Specimens of stream tin have been occasionally shown 
us, but under circumstances which threw much doubt on their authenticity. 
The occurrence of cinnabar with native gold, which has been repeatedly 
noticed in the Coast Ranges, is also not unknown in the Sierra, A specimen 
of washings, described as having come from near Placerville, consisted of 
rounded grains of pure cinnabar, with crystals of magnetite, globules and 
grains of lead, and scales of gold. This need not excite surprise, as the 
writer has seen in the auriferous slates quartz veins containing well-defined 
crystalline masses of cinnabar, which were small in size, but extremely pure. 
Section LX. — Economical Considerations relating to the Working of the Gravels. 
Although this volume does not profess to concern itself especially with the 
economical aspect of the hydraulic mining business, yet a large amount of 
information in this department has been gathered in the course of the inves- 
tigation, as will be seen by reference to the preceding chapters and the 
Appendices A and B. It is proper, therefore, to pass in review the principal 
facts, and to devote a few pages to setting forth such of the conclusions which 
ean be drawn from them as may seem of special importance. 
The first question would naturally be, What is the total yield of gold from 
the hydraulic mining operations? An answer to this question is desirable, 
as enabling the reader to form a correct idea of the magnitude of the busi- 
ness, the scientific side of which has been that most prominently presented 
in the course of this work. As is well-known, all statistics of the yield of 
the metals in this country are of the nature of guesses, more or less to be 
depended on in proportion as the parties guessing have had favorable oppor- 
tunities for forming an opinion, and have been qualified by natural ability 
and education to make a good use of such opportunities.* 
The yield of gold in the most productive years of gold mining in Cail- 
fornia, 1851-1853, was estimated by the present writer at from $62,000,000 
* It is hardly necessary to add that disinterestedness is also a sine qua non in forming a valuable opinion in 
relation to the value and yield of mining property. 
