THE CULTIVATOR. 
171 
notion is founded. For example, he enters the labora¬ 
tory, where he is surrounded by gentlemen engaged in a 
great variety of investigations. Here is one upon Ben¬ 
zoic acid, there one upon Hippuric acid, there one upon 
Allantoin: there one upon the Cyanogen compounds, 
here one upon a new gum, here one upon cheese, there 
others upon bread—and so on, all of them engaged in ori¬ 
ginal investigation. He is ready to tell them the results 
for which they may look. Such is his familiarity with 
every fact in known chemistry, that its analogies are per¬ 
petually present, and enable him to premise almost any 
thing with regard to problematical investigations. 
He comes to a gentleman who has a new substance. 
The Professor directs him to bring a dozen test tubes, 
and perhaps an equal number of re-agents. The unknown 
substance is in a few moments distributed among the test 
tubes awaiting the reactions. He goes on through the 
laboratory repeating similar experiments with other gen¬ 
tlemen; and the next day when he comes round again, if 
a test tube has been removed from its place, he knows 
it; moreover, the gentleman who by mistake leaves a 
process for a night, which ought to have been concluded 
at once, not unfrequently finds it, on his return the next 
morning, removed to the Professor’s private laboratory. 
This vigilant surveillance, this powerful local memory, 
this readiness in affording explanation in all difficult mat¬ 
ters connected with chemistry, have induced the expres¬ 
sion of the above opinion. However, Liebig has quite 
deprived the opinion of its poetry, for he has said, for the 
encouragement of all his pupils, that every fact in the 
science cost him labor to acquire and labor to retain; 
and though now ready to pronounce upon the history 
and properties of every known organic and inorganic 
compound, he has acquired (his prodigious mass of sci¬ 
entific information, only with prodigious labor. 
Respectfully yours, E. N. Hqrsford. 
MR. NORTON'S LETTERS—No. XI. 
Prof. Johnston's Leelxtres—Refuse of Distilleries—Sugar 
Cane—Silicate of Lime—Patent Manure—Guano Birds. 
Lab. of Ag. Chem. Association, Edinburgn, March 19, 1845. 
Mr. Tucker —I had the pleasure yesterday of attend¬ 
ing the first of a series of monthly meetings, which are 
to be held by the Ag. Chem. Association in conformity 
with one of their rules as to the duties of the chemist, by 
which he is required to devote a certain portion of his 
time to giving advice to members of the Association 
wishing the benefit of his counsel, and to communicate 
both the results of inquiries in the laboratory, and of his 
journeys through the country. Prof. Johnston, untiring 
in his efforts for the good of the agricultural community, 
exerted himself so successfully to make this meeting in¬ 
teresting and profitable, that I cannot do better than to 
notice some of the subjects which were brought forward. 
The report of proceedings during the past month, was 
opened by an account of lectures which Prof. Johnston 
had delivered at Linlithgow and Colinsburgh. 1 neard 
both of these lectures, and saw the eager and delighted 
audiences who pressed forward to catch every word. Ap¬ 
plications have since been made requesting their publica¬ 
tion. 
In mentioning some of the subjects that have been late- 
ly investigated in the laboratory, the first touched upon, 
was the refuse liquor of distilleries. Now distilleries in 
our country, I am happy to say, are diminishing in num¬ 
ber, yet it is interesting to know that the residue after the 
first distillation, contains substances that are highly nutri¬ 
tious, and also valuable as manures. A large quantity of 
phosphate of lime is present, and constitutes much of its 
value. The “dunder,” or refuse from the distillation of 
rum in the West Indies, has also been examined here, 
and found to be quite valuable. In connection with the 
same subject, was analysed the ash of the sugar cane, and 
the intelligent planters, instructed by the result, are now 
effecting a great saving by the restoration of it, as well 
as the dunder, to their land. 
In my last letter, I made some remarks upon the sili¬ 
cate of lime. Prof. Johnston at this time, brought for¬ 
ward the same subject, illustrated by an analysis of a slag- 
sent from one of the iron smelting furnaces in Ayrshire. 
Mr. Cameron, fourth assistant in this laboratory, analysed 
it with the following results: 
Alumina,. 25.36 per ct. 
Lime,. 39.47 
Magnesia,. 22.75 
Silieious matter,... 32.19 
99.77 
The quantity of lime, it will be noticed, is very large, 
but being in the state of silicate, it will therefore not be 
immediately available for the growth of plants, especial¬ 
ly while it remains in hard masses. The gentleman who 
sent it says, however, that it may be crushed for a shil¬ 
ling a ton. In this finely divided state, it may be appli¬ 
ed with much advantage, as its decomposition, constant, 
though slow, will furnish an unfailing supply of lime. 
Of course it should not be compared with limestone or 
marl, but it may be very valuable where neither of the 
other two can be readily obtained. It might be laid on 
in large quantity without fear of injury to the land. 
The Cornwall Patent Manure, and the Salduha Bay 
Guano, which I also mentioned in my last, were comment¬ 
ed upon, and the unfounded pretensions of the Cornwall 
manure exposed. Mr. Fromberg, the first assistant, has 
just analysed a sample of guano, from a cargo just arrived 
from Possession Island, a new locality. The following 
is his result: 
Water,. 12.72 per ct. 
Organic matter and ammoniaeal salts,. 42.60 
Common salt and sulphates and phosphate of pot¬ 
ash and soda,.1. 15.11 
Phosphates of lime and magnesia,. 15.95 
Carbonate of lime,. trace. 
Insoluble silieious matter,. 13.38 
This is by no means equal to the best samples from South 
America or Ichaboe, but will compare well with some 
of the inferior cargoes. It is probably at present prices, 
worth about £6 per ton. 
As guano begins to fail, they are bringing home the 
bodies of the birds themselves. Some of them were late¬ 
ly sent here, in order that their value as a manure, com¬ 
pared with that of guano, might be determined by Prof. 
Johnston. They had lain buried for years untler the gu¬ 
ano, and in appearance resembled the smoked geese from 
the Shetland Islands, sold in the shops here. They arc 
quite saturated with ammonia, and their large bones add 
much to their value. They would require chopping into 
small fragments before depositing in the soil, anti in con¬ 
sideration of this serious drawback, Prof. Johnston con¬ 
siders them worth about j£4 per ton, or nearly $20. 
Were it not for this difficulty, they would be worth as 
much as guano itself. 
The remainder of the time alloted to the meeting wa» 
occupied by a discussion as to the best means of preserv¬ 
ing the immense quantity of manure carried into the 
sea by the sewers of the city. 
The next meeting is on the 9th of April, and a most 
interesting list of subjects is proposed. Of this I may al¬ 
so give you a sketch in a future letter. 
Truly yours, John P. Norton. 
MR. NORTON’S LETTERS—No. XII. 
Edinburgh, April 27, 1845. 
L. Tucker, Esq.— It has occurred to me that in addi¬ 
tion to my own letters, a series of practical papers from 
one of the farmers of the Lothians, a body of men con¬ 
fessedly surpassed by none in any part of the world, 
might be both interesting and highly instructive to the 
readers of your paper. Mr. Girdwood has kindly volun¬ 
teered his services, and I may say without flattery, that 
very few, even in Scotland, are so well qualified for such 
a task. I cannot help saying that I sometimes disagree 
with him in theory, as for instance in theprlfcent article, 
I would have based the theory of rotation upon the phy¬ 
sical condition as well as the inorganic constituents of 
the soil, but in practical matters I would bow to his de¬ 
cision. Without further preface, I am sure that your 
readers will be benefited by the advice of one who unites 
the practical wisdom of the Lothians to the enthusiasm 
