173 
weather. I saw also a kind of repeating musket with two locks* 
one behind the other. With such muskets, by means of the 
anterior lock, twelve consecutive discharges can be produced* 
and these being over, the gun is loaded again like an ordinary 
infantry musket, and fired by means of the lowest lock. After 
the anterior lock is fired, all the remaining shots incessantly 
follow, and cannot be withheld at will, as it is the case with the 
repeating gun bought by me in New York, already described* 
It is yet unknown how this successive firing can be obtained. 
Captain Booth showed me also double screws of his own inven¬ 
tion, the object of which is to supply the place of ordinary lan¬ 
yards for ships. This officer has obtained a patent for his con¬ 
trivance, and it has been adopted, for experiment, in the frigate 
Brandywine; in the same navy-yard is a laboratory, under the 
arsenal, where the necessary fire-works for the artillery are 
made. The place seemed to me to be ill chosen, since an ex¬ 
plosion that may easily happen in such an establishment, might 
cause most terrible consequences to the navy-yard. 
Over the Potomac there is a long wooden bridge, built upon 
ordinary cross-beams. I measured it, and found it to be fifteen 
paces broad, and one thousand nine hundred long. My paces 
being to the ordinary ones in the relation of four to five, it may be 
assumed that it is about two thousand three hundred and seventy- 
five paces in length. It required nineteen minutes to walk from 
one end to the other. Every foot-passenger pays six cents. This 
bridge astonishes by its length, but not at all in its execution, for 
it is clumsy and coarse. Many of the planks are rotten, and it 
is in want of repair; it has two side-walks, one of them is sepa¬ 
rated from the road by a rail. It is lighted by night with lanterns. 
It is provided with two drawbridges, in order to let vessels pass. 
It grew dark before I returned home, and was surprised at the 
stillness of the streets, as I scarcely met an individual. 
Patents of invention are issued from the patent-office; whoever 
wishes to obtain a patent for an invention, is obliged to deliver a 
model or an accurate drawing of it. These models are exposed 
in an appropriate place, where they remain until the expiration 
of the time for which the patents are granted; they are then put 
into the lumber-room. Among such models, there certainly is 
a great number of things of little importance, as for instance, a 
contrivance for peeling apples; there are also ninety-six models 
for making nails in different ways, but some of them very re¬ 
markable. The most interesting models of machinery seemed 
to me to be those intended to remove mud from the bottoms of 
rivers and canals, or to make them deeper. One of them con¬ 
sists of an ordinary steam-boat; with her they go to the spot 
where they are to work; arrived at the spot they cast anchor, 
