612 Transactions of the American Institute. 



shut off the view of the golden stubble fields beyond, and finally 

 merged into the edges of the Tule lands. These are low-lying, level 

 tracts of great extent, and covered with a vegetation that, at a dis- 

 tance, looks like tall and waving corn, but is, in reality, only a kind 

 of flag; something the same as that which grows on moist ground in 

 New England, but twice as high and far more thrifty. Were these 

 flag-covered fens diked and drained, as they will be some day, they 

 would make fields among the finest in California, for their soil is 

 unrivaled in fertility, and they would know no lack of water such as 

 has, the past summer, made the famed valley of the San Joaquin like 

 a bed of ashes. Slowly the Tules receded from the sight, as the low 

 pressure engine, carrying but twenty pounds of steam, steadily drove 

 the boat out upon the broad-reaching waters of the bay. Here, as I 

 remember, just as the sun went down, a stern-wheel steamer, of odd 

 shape and swift motion, passed us, throwing a distorted and fantastic 

 shadow upon the low, wide waves. A few minutes after ten o'clock 

 we came to the wharf at San Francisco, and I had reached the west- 

 ern limit of my tour. 



Dr. Feuchtwanger — Our friend has given us a very glowing and 

 graphic account of the silver mining in Nevada. I have been 

 delighted with it, because it recalls to my memory what I witnessed 

 in the same region eight years ago. But he has omitted to mention 

 the fact that the matrix of the silver ore is a white limestone, which 

 looks like snow. 



The thanks of the association were tendered to Prof. "Whitney for. 

 his interesting paper. 



The Secretary read the following paper : 



Tilghman's Sand-blast for Cutting Glass or Stone. 

 By Robert Weir, C. E. 



A new invention by B. 0. Tilghman, Esq., of Philadelphia, known 

 as " Tilghman's sand-blast," for cutting stone, glass or any hard sub- 

 stances, of such a nature, is cow being exhibited at the American 

 Institute fair, and from its simplicity and quick action this process will 

 be sought after and applied to many purposes in engineering and the 

 arts, which may not at first occur to our minds. 



It may well be said there is nothing new under the sun, when we 

 see the marvelous results of Tilghman's process ; for here has a man 

 made use of one of nature's most common and constant actions in the 

 way of lifting or driving the sand with the winds or waters, and 

 wearing or cutting away the hardest substances. In this process the 



