77 
upon a New Constructicm. 
bination is shewn in Fig. 4., where mni^ the piece of metal in 
which the aperture is made. 
When the lenses have the size shewn in the diagrams, it 
would be advisable to place the aperture in the centre of a mir- 
ror, muj Fig. 5. made of such a convexity as to reflect upon the 
object those converging rays which pass through the first lens. 
By these means we may communicate the periscopic principle 
to single microscopes, at the same time that we remedy the loss 
of light occasioned by the doubling of the surfaces, or correct the 
aberration arising from the diflerent refrangibility of light. 
Edinburgh, May 1820. 
Art. XIII. — Some account of a suspended Plant qf Ficus 
Australis^ which has grown for eight months without earth 
in the Stove of the Botanic Garden at Edinburgh. By 
Mr William Macnab, Superintendant of the Garden. 
Communicated by the Author^ 
Ficus Australis is a native of New South Wales^ and was 
introduced into the British gardens in 1789, by the Right Ho- 
nourable Sir Joseph Banks. The plant is not uncommon now 
in collections in this country, where it has been usually treated 
as a greenhouse plant ; and in a good greenhouse it thrives 
tolerably well, although it seems rather more impatient of cold 
than many of the plants from the same country. 
When I came to superintend this garden in 1810, I found a 
specimen of it among the greenhouse plants, where it remained 
for some time afterwards ; but owing to the bad construction of 
the greenhouse here, and the very hardy way in which I was 
obliged to treat the plants in that department, I did not find 
the Ficus thrive so well as I had been accustomed to see it do. 
I concluded that it required more heat, and in the spring of 
1811 I placed it in the stove, where it soon began to grow as 
vigorously as I had ever seen it do. 
After it had been in the stove for some time, I observed a 
root set out of the stem, about a foot above the earth of the pot 
in which it was planted. I may observe, that this tendency to 
