E. W. Mbrley — Self- Acting Mercurial Air pump. 439 



On Tourmaline. 



An examination was also made of some large tourmaline 

 crystals which came from Rudeville, !N". J. This place is about 

 three and one-half miles northeast of Franklin Furnace, and 

 on the same belt of white limestone that contains the zinc 

 ores. The limestone here is pierced by a large dike of so- 

 called mica-diabase, as described by F. L. Nason* and which 

 has lately been shown to contain more or less altered leucites.f 

 The tourmalines occur near the dike and their formation is 

 apparently due to its action. Other green and brown ones of 

 great perfection have been obtained in the white limestone 

 quarry near the furnace at Franklin. They are there asso- 

 ciated with a granite dike. 



Most of the crystals are dark brown in color and have well 

 defined faces. The largest one in the lot has the common tri- 

 angular form of prism, bounded by three broad ooP faces, 

 measuring four inches in width, and narrower ooP2 faces. 

 The prism is capped by the negative rhombohedron — R, and 

 a large basal plane which completely cuts off the polar edges 

 of the rhombohedron. This crystal is shown_ in fig. 6 — 

 m = oo P(1010) ; a = oo P2(1120) ; r = - K(011 1) ; c = OP 

 (0001). 



All of the forms identified on the crystals are as follows : 



ooP(1010) R(1011) 



OP(0001) -R(Olll) 



ooP2(112_0) — 2R(0'Z21) 



ooPf(4150) R B (3251) 



Much assistance has been rendered by Prof. J. F. Kemp, of 

 Columbia College, by suggestions and by the loan of the crys- 

 tals of allanite and tourmaline which he collected. The writer 

 takes this opportunity to express his acknowledgments. 

 Geological Laboratory, Cornell University. 



Aet. LIY. — A Self-Acting Mercurial Air pump • by 

 Edwaed W. Moeley, Cleveland, Ohio. 



Raps has devised an excellent self-acting Toepler air pump. 

 But a different method of driving such a pump is sometimes 

 convenient. For instance, the water pressure in my labora- 

 tory is not enough to actuate a mercurial air pump, while in 

 the lowest story of the building it will fairly suffice. It is 

 therefore desirable to drive the pump, placed on an upper 



* Ann. Eep. State Geologist of 5T. J.. 1890. pp. 35-36. 

 f J. F. Kemp. This Journal for April, 1894. 



