424 Experiments andOhervations on t fie Mass 



phofeKcent ai^perviance. I continued to bend the twi'i^ iihtii the 

 inilkv juice chfipped out, wlicn eacli drop was a drop of fire, very 

 mucli like what I h;'.ve seen on drop|)ing inflamed tallow. I did 

 not observe any particular smell, The milky juice is said to be 

 very poisonous; it is caustic, and occasions much itching and 

 irritation when applied to the skin. It becomes viscous in the 

 air, and soon dries of a yellowish colour, slightly tinged with 

 green, when it has tlie appearance of a gum-resin. 



The al)ove accor.nt contains all the information that I can 

 give you on the subject: — should vou think it deserving to be 

 laid before the Royal Society, I would beg of you to add your 

 observations, as they would render the communication inter- 

 esting. 



1 am, with sentiments of the highest esteem and respect, 

 My dear sir, 



Your faithful friend and devoted servant, 

 London, April 27, 1S16. A. F. MoRNAY. 



To Dr. Wollasion, 

 Secretary of the Royal Society. 



LXXXIV. Olservations avd Experiments on the Mass of Na- 

 tive Iro7i found in Brasil. By W. H. Wollaston, M.D. 

 Sec. R.S.'^ 



JL HE preceding letter from Mr. Mornay, relating to the dis- 

 covery of a mass of nati\e iron in Bahia, was drawn up at my 

 request, as a valuable addition to our stock of knowledge on that 

 most curious subject ; and I am in hopes that the results of my 

 own experiments may contribute something not uninteresting to 

 the Society. 



The specimen of the iron with which Mr. Mornay very li- 

 berally supplied me for experiment, though it necessarily bears 

 marks of the hammer bv which it has been detached, presents 

 also other surfaces, not only indicatina; that its texture is cry- 

 stalline, but showing also the forms in which it is ilisposed to 

 break, to be those of the regular octoliedron and tetrahedron, 

 or rhomboid, consisting of these forms combined. 



In my own sp£cimen, the cry.italline surfaces appear to have 

 been the result of a process of oxidation, which has penetrated 

 the mass to a considerable depth in the direction of its laminae ; 

 but in the specimen which is in the possession of the Geological 

 Society, the brilliant surfaces that have been occasioned by forci- 

 ble separation from the original mass, exhibit also the same 



* From the Transactions of the Royal Society for 181C, part ii. 



configurations 



