Fune 8, 1871 | 
previous years, as well as other data, including peculiarities 
in modes of manufacture, which may be useful for com- 
parison with the methods pursued and the results obtained 
at other factories. There can be no doubt that these 
efforts must sooner or later result in the formation of a 
dairy science, and in the establishment of sound theories 
of dairy management. 
But the functions of the American Dairymen’s Associa- 
tion are not confined to observation and experiment at 
home. Already the inquiries of its officers have enabled 
its members to improve their cheese-making practice by 
adopting some features of our Cheddar system ; and in the 
last volume of the Report of the Association is an able 
paper by Prof. Caldwell,* showing some features common 
to the numerous cheese-making processes followed in 
Holland, Switzerland, France, and Italy. One of the 
most interesting points brought out is the intimate connec- 
tion that exists between the ripening of cheese and the 
development and growth of Mccrococcus and other forms 
of mould. As a matter of commerce it is important to 
the farmer to ripen his cheese as soon as possible. This 
is done in various ways, all having for their object the 
introduction of large numbers of germs of the appropriate 
fungus. The ripening of Stracchino cheese is thus in- 
duced by the introduction of layers of old curd ; that of 
Roquefort by an admixture of mouldy bread, containing 
germs of Penicillium, and that of Brie by packing the 
thin cheeses between layers of musty hay. Another 
observation of interest is, that the presence of free am- 
monia in the curing-room hastens the ripening of the cheese, 
a fact which may have some bearing on the well-known 
property of American cheese (which is always packed 
in boxes) to ripen more rapidly than English makes. 
These evidences of a process of scientific investigation 
induce us, therefore, to regard the factories, or associated 
dairies, as they are termed, as possessing a scientific value, 
both as educational establishments and as laboratories. 
But, it may be asked, why is this not true also of the farm- 
dairy? Our answer is, that while the manager of a factory 
makes cheese-making his sole business, his success in 
which depends entirely on his skill and knowledge, the 
English dairy-farmer has little or nothing to do with 
cheese-making, but occupies himself with the manage- 
ment of his farm. With the production of the milk his 
supervision ceases, and the manufacturing process iseither 
carried on by his wife, who has household cares to occupy 
her time and thoughts, or by a dairymaid, who has no 
interest in the matter, and who knows that her services 
are at a premium. 
Thus, with the exception of the additions to our know- 
ledge of the vatzonale of cheese-making, for which we are 
chiefly indebted to Dr. Voelcker’s chemical researches, 
the manufacture of dairy products in England can hardly 
be said to have advanced during the last half century, 
while it has made enormous strides in America during 
the last ten years. Let us hope that the establishment of 
cheese-factories in England, commenced last year at the 
risk of some liberal-minded Derbyshire landlords,} may 
also be the dawn of an English era of progress in this most 
important agricultural industry. 

DBELLS 

HYDRAULIC BUFFER FOR CHECKING 
RECOIL OF HEAVY GUNS 
HE ingenious instrument, the name of which stands 
at the head of this paper, deserves some notice, 
not only on account of its utility for its purpose, but as an 
interesting method of meeting and overcoming those violent 
efforts of nature to which she is provoked by explosion. 
Tn the recoil of a heavy gun, we have an example of the 
greatest force which man attempts to control, The in- 
* Sixth Annual Report, Syracuse, N.Y., 1871, p. 25. 
+ Vide Journ. Royal Agric. Soc., vol. xxii. p. 29, and vol, xxiii. p. 170. 
t Ibid, 2nd series, vol. xii. p. 42. 
NATURE 

105 

ventions of Captain Moncrieff, which no long ago formed 
the subject of an article, seek to utilise this force; other 
gun carriages lead it to expend itself as harmlessly as 
possible. 
_ The Hydraulic Buffer accomplishes this latter object 
In a manner very ingenious, and affording some in- 
teresting illustrations of Nature’s laws; it also possesses 
several advantages over other methods which have been 
and are still used. For it the public service is indebted 
to Colonel Clerk, RA., F.R.S., Superintendent of the 
Royal Carriage Department in Woolwich Arsenal. Before 
the introduction of the Hydraulic Buffer into the English 
service, and in those cases where it is not yet applied, the 
method employed to overcome the recoil was the friction 
of iron plates. To the bottom of the gun-carriage several 
plates are fixed, which pass between long plates 
placed along the middle of the slide or platform on 
which the carriage runs ; and the friction of their surfaces 
in contact overcomes the force of the recoil, and brings 
the gun and carriage to a standstill. The amount of the 
friction can be regulated by the compression given to these 
plates, and requires to be altered for the various charges 
used. The compression must be taken off to allow the 
gun to be run forward to the firing position, and must be 
again set up to meet the recoil. 
The Hydraulic Buffer, on the other hand, is always 
ready for use, and never needs any adjustment. This is 
one of its advantages, and one which is of special im- 
portance in the heat and excitement of action. It 
consists of a cylinder (A B in figure) placed in the 
platform, and lying along its length. In the cylinder 
is a piston pierced with four holes, and the extremity 
of the piston-rod is attached to the carriage. When 
the gun and carriage are run out for firing, the 
piston is moved to the lower end of the cylinder 
(A), which is filled with water, except a small air-space 
exceeding slightly the cubic content of the piston-rod, 
so as to allow for the displacement of the water when 
the piston is driven to the other end of the cylinder, 
When the gun is fired, and with its carriage begins to 
recoil, the piston is driven back into the cylinder. The 
first effect of this is to compress the air in the cylinder 
very violently, then the water begins to run through the 
four holes in the piston, this motion soon attains a very 
great velocity, and in imparting this to the water, the force 
of the recoil is soon exhausted. Itis spent in transferring 
the water with very great rapidity through these orifices 
from one side of the piston to the other. 
This rapidity depends on the ratio of the area of the 
piston to the area of the four holes init. A very small 
diminution in the area of these orifices would cause the 
recoil to be checked very much sooner ; a correspondingly 
slight increase would allow the piston to strike with vio- 
lence against the end of the cylinder. It was found in 
an experiment with a 20-pounder gun, that when the holes 
were 0°562 of an inch in diameter, the recoil extended the 
whole length of the cylinder, 2ft. 9in., and struck violently 
the end of it; when a piston was used with holes 0°437in. in 
diameter, the recoil was only rft. 11in., and ended quietly, 
the same charge being used. Inanother experiment with 
a 12-pounder gun in a boat carriage the holes in the 
piston were five-eighths of an inch in diameter, the recoil 
was 2{t. 2in. ; when the diameter of the holes was increased 
by one-sixteenth of an inch the recoil was 3ft. 2in.* The 
proper ratio of the area of the holes to the area of the 
piston is evidently that which will allow the recoil to ex- 
pend its force in nearly, but not quite, the whole length 
of the cylinder. When once this ratio is fixed, it is very 
remarkable that the amount of the charge, or the slope 
at which the platform is placed, whether up or down or 
* The reason of this is evident from a little consideration: first, every ad- 
dition to the area of the holes diminishes the area of the piston, which acts 
cn the water; secondly the difference of the work done by the recoil is pre- 
portional to the difference of the sguares of the velocities given to the water 
in passing through the orifices in the two cases, 
