330 PROCEEDINGS OF THE CALIFORNIA 



Professor Gray enumerates, in his manual, only 2,426 species of plants as 

 occurring in the eighteen Northern United States and Canada East, embracing 

 an area of no less than 600.000 square miles. The whole of California and 

 Oregon includes only about 250.000 square miles, only a very small portion of 

 which could have been thoroughly explored by Mr. Wood ; how unlikely, then, 

 that he should have actually obtained, in nine months, 368 species more on 

 250,000 square miles, than all the botanists of the East have found on more 

 than double that area. Mr. Bolander also brought forward ample evidence to 

 show that Mr. Wood was not competent to determine how many new species he 

 had collected, proving by the written statements of Dr. Kellogg, and others, 

 that he was not acquainted with some of the most common and easily recog- 

 nized genera of this coast. 



Dr. Gibbons made some remarks on the rain-fall of this region 

 during the last seventeen years. 



Mr. Gutzkow exhibited a sheet of metallic silver of three feet in 

 diameter, and about three ounces Troy weight, which had the ap- 

 pearance and consistency of white writing paper. It was taken 

 from the surface of a lead-lined tank, in which a solution of prot- 

 oxide of iron was saturated, near the boiling point, with sulphate 

 of silver. If the temperature of the solution is maintained at a 

 certain height, sheet after sheet can be stripped off from the sur- 

 face. The silver thus obtained, is, after washing with muriatic acid 

 to free it from the iron solution, chemically pure, and by its pecu- 

 liar shape and purity, well adapted to serve as proof silver for 

 assaying purposes. The experiment will work only when operat- 

 ing on a rather large scale, so as to prevent the too sudden cooling 

 of the solution. The chemical action to which it is due is the oxy- 

 dation of the protoxide of iron into sesquioxide at the expense of 

 the oxygen combined with the silver. This oxydation, which is 

 known to precipitate the silver as a whitish powder, begins to take 

 place only at a certain temperature below the boiling point, and is 

 made, in the above experiment, to act on the crystals of sulphate of 

 silver separating on the surface of the slowly cooling solution. 



