136 TRAVIS— PYRITE FROM CORNWALL. [June 22 



off the upper corner of the latter face. Considerable difficulty was 

 experienced in measuring them, as they were brilliant only when 

 quite small ; the larger faces were poor and rounded. 



(421) Only one face was observed; crystal 6 shows a small face 

 whose intersection with (210) is sensibly parallel with the centre 

 line of the latter. It is about i mm. long by 0.5 mm. wide. 



42l/\ III. 



Measured 28° 12' 



Calculated 28° 6^' 



(i3'7«3) was found to be common. The form was determined 

 from crystals 10 and 5. 



13.7.3 /\ 210. p 



Measured 8° 30' 11° 30' (No. 10; signal good) 



Measured 7° 55' n" 49' (No. 5 ; signal poor and 



Calculated 8° 29' 11° 37' divided into two. Angle 



given is mean position) 



Other good measurements are 



13.7.3 /\ 210. P 'P 



Measured 14° 05' 55° 40' (No. 8; signal rather 



Calculated 13° 57' 55° 4o' bright, but poor) 



13-7.3 A loo- P 'P 



Measured 23° 00' 30° 22' (No. 14) 



Calculated 23° 12' 30° 22' 



Besides the above, (13.7.3) was observed on crystal 13. 



(952) is a new form for pyrite. It affords smaller faces than 

 (13.7.3) ^^d while bright their smallness prevents any accuracy in 

 measurement. The form was determined from two sets of meas- 

 urements on crystals 4 and 14. 



952 A 210. p (}> 



Measured 11° 40' 11° 15' (No. 4; signal faint) 



Calculated 12° 36' 11° 15' 



As a difference of 1° in p is equivalent to 12' in actual position, the 

 above discrepancy is about 11'. 



952 /\ 001. p <f> 



Measured 28° 45' 79° 06' (No. 14; signal poor) 



Calculated 29° 03' 79° 12' 



(952) was also observed on crystals 5, 9, 10, and 12, giving meas- 

 urements sufficiently good to identify the form after its occurrence 

 had been established by the above. 



