Prof. Maskelyne and Dr. Lang's Miner alogical Notes. 503 



which are the means of numerous measurements — the first angle 

 being observed on crystals from Siegen*, the two others on cry- 

 stals from Nijni Tagilsk. 



Including the new planes on the crystals I am going to de- 

 scribe, we have for malachite the planes 



100, 010, 001, 110, 101, 102, 103, 104, 

 124, 134, 123, 112, 323, 221, 



for which we find the following angles calculated with the above 

 elements :— 





100. 



010. 



001. 



110. 



110. 



001 



88 57 



90° d 



O I 





 89 10 



89° 10 



89° 10 



110 

 101 



37 58 



52 2 







75 56 



61 53 



90 



27 4 



68 11 



68 11 



104 



96 19 



90 



7 22 



94 59 



94 59 



To 3 



98 43 



90 



9 46 



96 53 



96 53 



102 



103 29 



90 



78 39 



14 32 



100 36 



100 36 



124 



96 11 



13 30 



87 56 



101 54 



13 4 



96 3 



73 15 



18 15 



84 36 



106 32 



"123 



98 25 



75 8 



17 44 



87 34 



105 52 



112 



103 14 



78 54 



18 13 



93 33 



107 23 



323 



114 38 



76 11 



30 32 



101 11 



119 11 



221 



128 16 



60 27 



53 10 



100 39 



142 20 



The folio wing newly observed combinations are, like all crystals 

 of malachite, twinned on the axis (10 0). 



Plate VII. fig. 1.— 10 0, 101, 2 21. 



Tbe specimen on which this by no means small crystal occurred 

 consists of larger crystals penetrating each other. But this crys- 

 tal was the only one of which at least one end, formed by the 

 enumerated planes, was not in contact with other crystals. The 

 planes 1 1 on the top seem to have been produced by cleavage. 

 The planes 2 21 are not good, and are striated parallel with 

 their intersection with the prism 110. 



The observed angles are 



* These crystals were already described in the previous Note. 



