February 12th, 1907.] PROCEEDINGS. xxi 



arrow heads and obsidian chippings found by him in an Indian 

 encampment, June, 1906, on Gold Hill, Cascade Range, near 

 Eugene, Oregon, U.S.A., also specimens from the obsidian cliff 

 in the Yellowstone Park, Montana. 



Some modern and prehistoric pottery, a cinerary urn, and 

 stone axe-head from the old Aztec ruins and the Indian pueblo 

 of Acoma, New Mexico, and many beautiful specimens of 

 petrified wood were also shewn, these latter from the petrified 

 forest of Adamana Apache, County Arizona, where there are 

 thousands of acres in places thickly strewn with trunks and 

 segments of trees, the ground being covered with chip-like 

 fragments of agatized wood. 



Lantern views of the forests and the natural log bridge, 200 

 feet long, which spans a chasm 60 feet wide, and other interesting 

 views of Indians and scenery in New Mexico, Arizona, and 

 other parts of the States, taken during a visit made in April and 

 May, 1906, were thrown on the screen. 



Mr. J. E. Petavel, M.Sc, gave a short description of 

 various forms of apparatus which he has designed for experi- 

 mental work at very high gaseous pressures, and mostly in use 

 at the Physical Laboratories of the Manchester University. 



The details of construction were illustrated by numerous 

 lantern slides. 



Special attention was paid to an improved hydraulic pump, 

 capable of adaptation to many uses, and attaining a working 

 pressure of 2,000 atmospheres. 



A method which has proved satisfactory for compressing 

 pure gases by forcing glycerine into a cylinder containing the 

 gas was also fully explained. 



The pressures dealt with ranged from 3,000 to 30,000 lbs. 

 per square inch. 



Mr. C. G. Hewitt, B.Sc, read a paper by Mr. A. D. 

 Darbishire, M.A., entitled "Some Tables for explaining 

 the Nature of Statistical Correlation." 



