On the Effects of Mildew on Canvas. 315 
three pieces were damped, and placed in a situation to bring on 
mildew. The results were as follows: 
P. Browell and Company. 
Aug. 30. Quite sound. 
Sept. 1 6. Quite sound. 
28. Begins to grow 
blackish. 
Oct. 21. Black and yellow 
spots. 
31. Entirely rotten. 
Q. Sanderson , 
Quite sound. 
Quite sound. 
Quite sound, a little 
mouldy. 
Quite sound, mould go- 
ing off. 
Quite sound and clean. 
R. Unprepared . 
Mouldy. 
More mouldy. 
Very mouldy. 
Rotten. 
On the 24lh May two pieces of canvas, the one F, prepared 
by Sanderson, the other Z, prepared by Browell and Company, 
were exposed to damp. 
Y. Sanderson. 
May 15. Sound. 
24. Sound. Wet it. 
June 10. Sound and clean. 
16. Sound, but has lost colour. 
July 15. Darker, but perfectly sound 
and entire. 
Z. Browell and Company . 
Sound. 
Sound, Wet it. 
Very mouldy. 
More mouldy. 
Tears, and is quite unservice- 
able. 
Many other experiments might be adduced in support of Mr 
Sanderson’s claims, but as they have all the same result as the 
above, and differ but slightly as to the circumstances, it is un- 
necessary to detail them. Similar trials have been made with 
cotton bagging, and it has been found, that, while an unprepared 
piece had become rotten, another that had been subjected to the 
antiseptic treatment remained perfectly sound. The results of 
these several experiments we have witnessed in the pieces that 
had been submitted to trial ; and we feel perfectly authorised to 
recommend the preparation practised by Mr Sanderson, as com- 
pletely efficient, under all ordinary circumstances. 
The general character of the black spots or stains on the mil- 
dew canvas bearing some resemblance to certain minute cryptoga- 
mic plants, the Editor requested Dr Greville to give him his opi- 
nion, which he obligingly did in the following note : — i£ I have 
very carefully examined the black spots on the piece of canvas 
you placed in my hands, and am of opinion that they are caused 
(in part, at least) by a minute cryptogam ic plant. I have traced 
the sporules, which are of a subglobose form and transparent. 
