Geology and Mineralogy. 429 



especially to those engaged in the construction of standard coils 

 and instruments, or in the actual work of electrical measurement. 



A. w. w. 

 14. Practical Work in General Physics. By W. G. Wooll- 

 combe. Crown 8°, pp. xii, 83. Oxford, Clarendon Press. 1894. 

 — This is a collection of some fifty practical exercises, with 

 descriptions of instruments and methods for the measurement of 

 lengths, areas, volumes, and densities. Other topics are the 

 barometer, the simple pendulum, capillarity and surface tension. 

 The theory of the balance and the methods of determining 

 weights are briefly indicated, with practical directions sufficient 

 to prepare the experimenter for such use of the balance as is 

 required in many of the exercises. The experiments, which are 

 mostly of rather simple character, are clearly described with con- 

 siderable detail, and, for the limited range of subjects, the book 

 will be a useful guide to the student. a. w. w. 



II. Geology and Minekalogy. 



1. An Occurrence of Anorthite and Epidote (communicated). 

 — In a large series of specimens collected at Phippsburg, Maine, 

 by T. F. Lamb of Portland, these two minerals occur under un- 

 usual circumstances. The mass of the material consists of cinna- 

 mon garnet, with occasional green pyroxene, similar to the well- 

 known occurrences at Raymond, Maine, and elsewhere, the rock 

 itself being evidently a highly metamorphosed contact limestone. 

 Occasionally there is imbedded in the masses of garnet a dark 

 gray mineral, nearly black, in brilliant plates, in nowise suggest- 

 ing epidote. This however, it proved to be, after partial analysis 

 by Dr. W. F. Ilillebrand, and optical examination by Mr. J. S. 

 Diller. The anorthite, also verified optically by Mr. Diller, and 

 by partial analysis by Mr. George Steiger, is associated some- 

 times with the epidote, and sometimes in coarse crystals, only 

 with the garnet. The analyses are as follows : 



Epidote. Anorthite. 



SiO a 38-54 45-62 



A1 2 3 28-39 35-29 



Fe 2 "0 3 6-89 



FeO -50 



CaO 24-12 17-31 



MgO trace 



Ignition 2-26 



100-70 98-22 



On first inspection I supposed the epidote to be axinite, which 

 is said to occur at the Phippsburg locality, and which in this case 

 it somewhat resembles. f. av. clarke. 



2. A new locality of true Emeralds (communicated). — In July, 

 1894, a new locality of true emeralds was discovered, by Mr. J. 



