314 
On the Effects of Mildew on Canvas. 
the whole canvas used, previously to its being delivered from 
the stores, and while exposed to damp and wet in the ship, is 
so greatly deteriorated, that it never can wear so well, as if the 
generation of mildew were entirely prevented. For there is no 
canvas whatever, twine-canvas not excepted, that is not more or 
less liable to mildew and putrefaction. 
On the supposition, that the Navy requires only 20,000 bolts 
annually, at L. 3 per bolt, making in all a sum of L. 60,000, 
Mr Sanderson shews, that, by applying his antiseptic prepara- 
tion to unbleached, or what is termed boiled canvas, the whole 
annual saving would be L. 24,500, which is equal to one-third 
of the value of the whole annual consumption of the Navy in 
time of peace. 
In the exportation of cloths manufactured of flax and cotton, 
also, it is no uncommon thing for large quantities of it to be 
rendered unfit for use, from the injury it sustains from mildew, 
in its transit from this country to the foreign market ; and such 
cloth has frequently been sold for one-sixth of its proper value. 
So sensible are, in fact, the underwriters now of the loss sustained 
by cotton bagging from mildew, that they will not insure any da- 
mage that may occur on the passage. As an example of the 
benefit that might be derived from the preparation of cloths of 
this sort, it may be stated, that, upon the quantity of cotton 
bagging alone, annually exported by a single town in Scotland, 
Dundee, (it being estimated at 3,900,840 yards), merely by the 
additional expence of one-penny per yard, a saving would be 
secured to the merchant of not less than L. 30,000 per annum, 
which otherwise would be destroyed on the voyage to the foreign 
market. 
^ The most decisive experiments have been made upon the com- 
parative merits of Mr Sanderson's mode of preparation, with those 
already in use, and the results have been highly satisfactory. 
With the view of preventing all doubts as to the efficacy of his 
mode, a few of these experiments may be briefly detailed. 
On the 21st of August last, apiece of common canvas, No. I. 
prepared by Browell and Company, London, marked P, was 
put in competition with a similar piece of common canvas, 
No. IV. cured by Mr Sanderson, marked Q. At the same time, 
a piece of common canvas, unprepared, was put on trial. The 
