Proceedings, fyc. liii 



Organic matter (minus ammonia) 19.70 



Available ammonia '57 



Soluble alkaline chlorides and sulphates 1.64 



Phosphates of lime and magnesia (bone earth) 41.50 



Sulphate of lime (gypsum) 2.89 



Water 21.96 



Siliceous, or sandy matter 11.74 



100.00 



Dr. Macadam concluded by pointing out that the guano differed 

 from Peruvian guano, specially, in the comparative absence of 

 ammonia and soluble salts — results to be expected from the action 

 of rain in this climate. From the abundance of earthy phosphates 

 in the guano, it seemed to be specially adapted as a manure for grain 

 crops, though experiments had also proved its applicability to green 

 crops. 



A discussion ensued, in which several members took part. 



Dr. Macadam exhibited some specimens of black sand from the 

 Nicholson Diggings, which contained about 38 lbs. troy weight of 

 gold to the ton. The specimens were represented to have been 

 obtained from some tributaries of the Yarra in Gipps Land. It was 

 not in his power to inform the members of the Institute of the 

 exact locality, although parties had already visited the spot, and 

 bringing samples with them, had brought the same under the notice 

 of the Government. The sand was removed from the bed of the 

 Yarra, and was of a dark appearance, indicating the presence of a 

 large proportion of what was commonly called black sand. 



The specific gravity was 4.975. Gold particles were very generally 

 distributed throughout the whole mass, and in unusually large 

 pieces. The composition of the sand in 100 parts was as follows : — 



Per-oxide of tin (tin ore, equal to 19.2 per 



cent, of metallic tin) 24.410 



Gold 1.408 



Sand, including traces of iron, fragments 



of toivrmalin, rubies, &c 74,182 



100.000 



The richness of this sample in tin ore is much below the average, 

 having only about one-third of the average value. On the assump- 

 tion that tin pre is worth £75 per ton, this sample would be worth 

 about =£25 per ton. 



The remarkable per centage of gold is the principal feature in the 

 results of this analysis ; amounting in all to nearly one and a half 

 per cent, of the gross weight. 



This amounts in the ton of 2,240 lbs. avoirdupois, to 31.5392 lbs. 



