306 PROCEEDINGS OF SECTION B. 



A third portion was scraped on both surfaces before crush- 

 ing. The outer crust or scrapings — 5*25 grammes — gave a 

 yellowish brown-coloured powder, which was wholly lifted 

 by the magnet ; the inner dark and crystalline part, weighing 

 432 grammes, gave a brown powder and was also entirely 

 magnetic. 



Cakes of this and other rusts, ^ to -^^ inch, and of 3 or 4 

 inches superficial area, are drawn to a horse-shoe magnet 

 capable of sustaining a pound weight of iron, wath a slight 

 jump like pieces of thin sheet-irpn, but with, as might be 

 expected, very much less readiness. 



No. 3. — Must from an old wrought-iron 4:00-gallon water- 

 tank, made of thin " boiler " plate, and used for shipping 

 malt to Sydney. 



Specific gravity = 3*90 at 18° C. This had the usual 

 appearance of rust scales, but was strongly magnetic. Distinct 

 north and south poles were shown by some of the large 

 pieces ; 13*3 grammes were crushed and sent through a No. 

 60 sieve ; the brown powder was wholly lifted by the 

 magnet. A second sample, weighing 10*545 grammes, was 

 also found to be wholly magnetic. 



Another fragment or scale was crushed in an agate mortar, 

 and 10*205 grammes of an impalpable brown powder 

 obtained. This was placed in a glass spitz-kasten (or Knop's 

 soil-washing apparatus), and separated into three portions of 

 different specific gravities, but all were found to be attracted 

 by the magnet. 



The yellow ochre-like superficial rust from some of these 

 scales, 8*096 grammes in weight, was ground to an impalpable 

 powder and dried in a water-oven ; and even this was wholly 

 attracted by the magnet, although feebly. 



No. 4. — Rust from an old flue pipe, but which had never 



been used. 



Some of this was powdered and sent through a No. 60 sieve ; 

 the light brown coloured powder yielded 2*25 of strongly 

 magnetic and 2*3 grammes of feebly magnetic powder. 



No. 5. — Rusts from old bolts, hars, Sfc, which had been 

 lying exposed to the weather in a wooden box. 



Of the usual " rust colour " and appearance. The powder 

 yielded — Magnetic particles, 7*71 grammes ; non-magnetic 

 particles, "205 grammes, 



