Marriner. — The Mokoia Aerolite. 



183 



Heads, yet an explosion powerful enough to split the aerolite would easily 

 give a portion of the stone a southern direction, so that it would fall near 

 Wanganui. 



The stone at Mokoia, in its fall, cut a branch of a fir-tree {Pinus insiynis) 

 in two at a height of 108 in. from the ground, and then fell on to a root 

 that was growing on the surface of the ground and very much shattered it. 

 When a perpendicular was dropped from the broken tip of the branch to 

 the ground I found that the stone had travelled 46 in. due south from the 

 time that it struck the branch. .The branch was too small to alter its 

 direction in any way. 



By working from the above figures, I find that the fragments fell at an 

 angle of 66° 56' due south. 



Analytical Report 



I am much indebted to Mr. B. C. Aston, Chief Chemist of the Depart- 

 ment of Agriculture, who kindly analysed the stone for me. His report is 

 as follows : — 



" The fragment received for analysis consisted of fused globules inter- 

 spersed in a black metalhc oxide, while the centre of the piece contained 

 nodules of a softer siliceous matter, white, grey, and purple in colour. 

 The analysis below is probably only correct for the piece received, as the 

 meteorite is evidently not homogeneous in character : — 



99-51 

 The meteorite consists of the usual nickel iron generally found in meteorites 

 (but in this case it has been completely oxidized), together with such 

 sihceous minerals as augite and olivine." 



Dr. C. Coleridge Farr, Canterbury College, who tested a fragment of the 

 aerolite for its radio-active properties, says, " Your meteorite contains 

 0-438 X 10-12 gi-amme of radium per gramme of the meteorite. This is 

 rather low value, judging from the radium contents of terrestrial rocks. 

 The average of igneous rocks is about 1-7 x lO^^^^ or four times as great 

 as the meteorite, and for sedimentary rocks about 1-1 x 10 -i-, or nearly 

 three times as much." 



Petrological Description of the Mokoia Aerolite. 



Mr. R. Speight, M.A., B.Sc, Lecturer in Geology, Canterbury College, 

 forwarded me the following report : " Macroscopically the stone is of a 

 black - grey colour, with small rounded chondri of whitish appearance 



