SCIENTIFIC SUMMAET. 
317 
Bertin, and it is thus reported on bv the Committee appointed to sit upon it. 
The author gives in his memoir the results of experiments made on the 
decrease of rolling in calm water resulting from the passive resistance 
referred to, and the measurement of this resistance. He points out that the 
maximum amplitude of rolling is not sufficient to characterise ships with 
regard to the importance of their oscillations. Distinguish between the 
maximum amplitude, which M. Berlin proposes to call the mobility, and the 
mean and habitual amplitude which he calls the agitation, and which, 
relatively reduced, may be called by contrast the quietness (tranquillity). 
There are ships of great maximum rolling and of small maximum rolling, 
agitated and quiet, which must not be confounded with ships unstable and 
very stable : for very stable ships are in general very much agitated by 
rolling. To ascertain the laws of quietness in ships, it is necessary to mea- 
sure both the waves and the rolling ; and the instrument M. Berlin uses for 
this is one somewhat similar to that used by Mr. Froude. It consists of two 
pendulums, one of which takes 50 seconds and the other half a second in 
oscillation. Suppose a wave of 5 seconds, the period of the large pendulum 
will be ten times its duration, that of the smaller a tenth. If they are not 
too far from the axis of rotation of the rolling they will mark with reference 
to the ship’s vertical longitudinal plane, the first one the absolute rolling, 
the second the relative rolling of the ship on the normal of the wave ; pro- 
vided always (for the second assertion) the dimensions of the wave are con- 
siderable with reference to the volume of hull carried by it. The difference 
of these two angles will be the inclination of the waves. Tracing pencils 
fixed at the extremities of equal radii give two curves which can be easily 
examined and discussed. The Committee, says the Chemical News ” of 
May 30, speak of M. Berlin’s memoir as being one of considerable interest. 
A New Form of Mitrailleuse. — We are informed by the Scientific 
American” of April 12th, that some interesting trials have quite recently 
been made at the Holske Machine Works, 279 Cherry Street, in New 
York city, of a new mitrailleuse invented by Mr. J. P. Taylor, of Tennessee. 
The experimental gun, the first constructed, was built at the above estab- 
lishment, and possesses a number of entirely novel features, well calculated 
to make it a very formidable weapon. It has twenty-four barrels, which by 
simply turning a crank may be discharged en fusillade or all at once. The 
loading mechanism is especially ingenious, and consists in a magazine of 
cartridges, placed in rear of the gun, from which four rotating chambers are 
fed in succession. The contents of each chamber, as it comes even with the 
ends of the barrels, are discharged in turn until the reservoir is exhausted, 
when a new and filled receptacle may be quickly substituted ; 700 rounds 
per minute can be fired by fusillade, or 1,000 in broadside. The machinery 
is simple, and so arranged as to be well protected from the effects of shot 
striking it. The gun, which is exciting no small degree of interest in mili- 
tary circles, is at the present time undergoing a series of careful tests, the 
results of which, together with a full description and engraving of the piece, 
will shortly be published. 
Preservation of Corn, Grain, Hay, and Seed from Mildew, Heating, ^c . — 
The object proposed to be effected by this invention is the important one of 
protecting com, seed, and similar commodities stored in bulk from heat 
