84. REPORT—1868. 
In Mineral Chemistry, the application of the doctrines of atomicity to the for- 
mulation of natural minerals, in the new edition of Dana’s great work, constitutes 
an epoch in mineralogy which can scarcely fail to produce in that science results 
as important as those which this doctrine has already achieved in chemistry 
roper. 
: a Organic Chemistry, Hofmann’s discovery of a new series of cyanogen com- 
pounds imparts a new stimulus to researches on isomerism, and will long remain 
one of the great landmarks in organic investigation. 
In Kolhe’s laboratory the yearly harvest of synthetical discoveries has not failed. 
The direct conversion of carbonic anhydride into oxalic acid by Dr. Drechsel, and 
of ammoniec carbonate into urea by Basaroff, are amongst the most brilliant achieve- 
ments yet recorded in this branch of research. 
The artificial production of neurine by Wurtz illustrates strikingly the precision 
with which the results of chemical action can now be predicted. The atomic 
theory of Dalton, developed as it has been by the doctrine of atomicity, is rapidly 
assuming, for chemical phenomena, the position which the theory of gravitation 
occupies in cosmical science. 
After a long period of indecision and confusion, as regards the atomic weights of 
2 majority of the elements, it is gratifying to find that, at the present moment, an 
almost complete unanimity, prevails amongst chemical teachers. Out of upwards 
of 900 papers, worked in all parts of the United Kingdom, at a recent examina- 
tion connected with the Science and Art Department, the old atomic weights 
were employed in less than twenty cases. It is much to be regretted that this 
unanimity does not extend to notation and nomenclature; as regards the latter, a 
much greater uniformity prevails in France and Germany than in this country, 
and it is greatly to be desired that efforts should be made to bring about a better 
understanding on the subject. To the student a uniformly recognized nomencla- 
ture is perhaps of more importance than a generally accepted notation. For the 
present, the realization of the latter appears to be impossible ; but by a little mutual 
concession on the part of teachers, and especially of authors, there would be 
good hope of soon accomplishing the former. 
On the Chemical Composition of the Great Cannon of Muhammed IT., recently 
presented by the Sultan. Abdul Aziz Khan to the British Government, 
By ¥. A. Aner, FBS. 
This interesting example of heavy ordnance of early date, which has recently 
been added to the Museum of Artillery at Woolwich, is one of the large bombards 
which have, for about four centuries, occupied positions in the batteries on the 
Dardanelles. 
The gun consists of two parts, which are screwed together: each part weighs 
about 9 tons, the total weight of the piece being 18 tons 14 cwt. 3 qrs. Its ex- 
ternal form is cylindrical, the muzzle being as large as the breech; each end of 
either separate part carries a projecting moulding which is divided by cross-bars 
into recesses.. The object of these was not simply ornamental ; the recesses obvi- 
ously serve the purpose of the holes in a capstan-head, being required to give pur- 
chase to the levers employed in screwing the two parts together, and in moving 
the gun: Each piece has some simple moulding-ornamentation at the ends, and 
the external surfaces are subdivided by rings or mouldings about 14 inches apart. 
The total length of the gun is 17 feet, the diameter of the powder-chamber is 
10 inches, that of the bore is 25 inches. The two screws which join the pieces 
together, and are 23 inches in diameter, are skilfully cast. Some spherical stone 
ehen rere with the gun weigh 670 lbs.; the charge of powder required being 
ADS lbs. 
For the purpose of andlysis, specimens of the alloy were detached from different 
parts of the gun; these were found to vary considerably both in hardness and 
composition, Samples marked I. and IV. proved to be almost identical with the 
best descriptions of eun-metal of recent manufacture, whilst those in which the 
amount of tin was larger, exhibited specks of white alloy irregularly dispersed 
through the masses. On the other hand, Nos. IIL, I1la., and V. contain higher 
