called Sydneia or Terra Australis. 123 
Mr. Wedgwood was of opinion that these were a peculiar 
species of plumbago or graphite. Professor Blumenbach, on 
the contrary, regards them as molybdaena : and Mr. Klaproth 
believes them to be eisenglimmer or micaceous iron ore. 
When rubbed between the fingers, they leave a dark grey 
stain, and the feel is unctuous, like that of plumbago, or mo- 
lybdaena : the traces which they make on paper also resemble 
those of the abovementioned substances, but the lustre of the 
particles approaches nearer to that of molybdaena. 
In order therefore to determine whether or not they consisted 
totally or partially of molybdaena, I put the 85.30 grains into 
a small glass retort, and added two ounces of concentrated ni- 
tric acid. The retort was then placed in a sand heat, and the 
distillation was continued, till the matter remained dry. The 
acid was then poured back into the retort, and distilled as be- 
fore ; but I did not observe that the grey particles had suffered 
any change, nor were nitrous fumes produced, as when mo- 
lybdaena is thus treated. 
To be more certain, however, I digested pure ammoniac on 
the residuum ; and, having decanted it into a matrass, I eva- 
porated it to dryness, without perceiving any vestige of oxide 
of molybdaena, or indeed of any other substance. 
It was evident therefore that molybdaena was not present; 
and, as the general external characters and properties corre- 
sponded with those of plumbago, I was inclined to believe that 
these were particles of that substance, and not micaceous iron, 
as Mr. Klaproth imagined. To determine this, the following 
experiment was made. 
H. 200 grains of pure nitre in powder were mixed with the 
85.50 grains, and the mixture was gradually projected into a 
R 2 
