310 PKOCEEDINGS OF SECTION B. 



No. 16. — Rust from hot-water pipe, Prince Alfred Hospital, 

 Sydney. An ordinary li-inch pipe. 



Of a red brown colour, and feebly magnetic. 



No. 17. ~ Rust from cold-water l^-inch pipe, Prince Alfred 

 Hospital, Sydney. 



Partly magnetic. The non-magnetic portion contains 

 much organic matter. 



No. 18. — Rust from screw and nail, which had been exposed 

 for a few months on a window sill. 

 They were both covered with a thin coat of dark brown 

 oxide. The rust from both was attracted by the magnet, but 

 not wholly ; the quantity was small, and no attempt was 

 made to weigh or estimate the amount. 



19. — Rust from old holt. 



A small part of this was non-magnetic, but became feebly 

 attracted after boiling in water. 



The writer has on various occasions cited the skin of 

 magnetic oxide on meteorites as a pi'oof of the high tem- 

 perature to which they have been subjected in their passage 

 through the atmosphere ; but in some cases this may perhaps 

 have been found in the ordinary way, inasmuch as the fore- 

 going experiments seem to show very clearly that the oxides 

 yielded by the atmospheric rusting of iron may also be 

 magnetic. 



Experiments on the Rusting of Iron. 



While the volume has been going through the press I 

 have been able to obtain additional results from certain 

 experiments w^hich were going on when the paper was read, 

 especially those upon sheet iron, nails, &c. which had been 

 placed out to rust or immersed in cylinders of distilled 

 water, &c. 



The results do not differ from those already obtained and 

 stated when the paper was read, but the extra time has 

 enabled me to get thicker and heavier deposits of oxide, 

 which are mure satisfactory than thin films. 



Black sheet iron was scoured with pumice-stone until per- 

 fectly bright, clean, and free from scale, and cut into strips 

 7x2 inches. The strips were then put up into lots of about 

 1 lb. each. 



