296 Reports of the Chemical Committee. 
This g^uano is jrenuine Peruvian guano, but it will be seen 
that it contains a large proportion of the dehris of the rock on 
which the guano was deposited, and yielded little more than 
10^ per cent, of ammonia, or only about two-thirds the amount 
of ammonia which Peruvian guano of fair average quality used 
to contain. 
Messrs. Thompson, Bonar, & Co., the Peruvian Government 
agents for the sale of guano, have recently acquainted their 
customers that they have no more Chincha Island guano for sale 
in London, and they offer now Guanape Island guano at a reduced 
price, and quote the price of Government Peruvian guano at 121. 
per ton. 
Guanape guano, as far as Dr. Voelcker's experience goes, varies 
in composition to a greater extent than Peruvian, and the better 
samples are not equal in value to Peruvian guano. It is, there- 
fore, highly desirable that purchasers of Guanape Island guano 
or Peruvian Government guano should know what the quality 
is of the guano that is offered at a reduced price, and they are 
strongly advised to insist upon being supplied by the dealer with 
an analysis guaranteeing the quality of the particular cargo of 
guano which is offered for sale. Like other guanos varying in 
composition, Guanape guano should not be sold at a uniform 
price, but at rates corresponding with the intrinsic commercial 
value of different lots, which can only be ascertained by an 
analysis that may be fairly expected to be presented by the dealer 
to intending purchasers. 
5. Rape cake is frequently so full of wild Mustard that it 
cannot be safely used for feeding purposes. 
Several cases of rape cake quite unfit for feeding purposes were 
brought under Dr. Voelcker's notice during the last quarter ; and 
in one instance such cake did serious mischief to the cattle which 
were fed upon it, being made from seed largely contaminated 
with wild Mustard seed.* 
6. Cases of adulterated linseed cakes have been referred to Dr. 
Voelcker lately from the neighbourhood of Market Deeping and 
Hertford, in which beech-nut and earth-nut cake were found in 
cakes with the mark of the maker indicative of the purity of the 
article. 
In these cases he made inquiries respecting the names of the 
dealers, but experienced unwillingness on the part of the buyer to 
have publicity given to the particulars, which deserve exposure. 
* I analysed four pieces of this cake for Mr. Percival Harlam. of Gilnow House, 
Bolton, who had bought it from Mr. J. Andrew, corn broker, Liverpool.— A. V. 
