Steam=Vessels.— Marine Barometer. 235 - 
case where it disengages itself the relations are definite; and a 
proportion of water with a proportion of barytes, of potash, of 
soda, of sulphuric acid, of nitric acid, &c., cannot be disunited 
by fire ; and the water is as essential to the composition of these 
bodies under that form, as oxvgen and a combustible are to their 
composition without water. 
STEAM FISH-CONVEYING VESSELS. 
The application of the power of the steam-engine to naviga- 
tion is now proposed to be extended to the important object of 
furnishing the metropolis with a regular and constant supply of 
freh fish at a cheap price. The variable manner in which the Lon- 
don market is supplied with this valuable article of food—its 
scarcity at one time, its over-abundance at another, and its dear- 
ness at all times—have long been matters of public complaint ; 
and are undoubtedly more the result of those detentions to which 
the fishing packets are necessarily exposed from their depen- 
dence on the winds and tides, than of any combination or arti- 
fice (as is vulgarly supposed). among the dealers in the article. 
A fishing company has accordingly been formed, for the convey- 
ance of fish from the coasts to the metropolis, whose vessels are 
to be strongly built, sea-worthy, and fast-sailing sloops, with the 
additional power of proceeding at option by sails or steam se- 
parately or united. They are to be fitted up with wells and 
suitable valves, so that the fish will be brought to Billingsgate 
alive in pure sea-water, at all seasons of the year, and London 
thus enjoy a luxury to which it has been hitherto a stranger. 
The construction of the vessels and engines has been intrusted 
to Mr. George Dodd, author of a work on Steam-Packets and 
Steam-Engines. 
IMPROVEMENT IN STEAM-VESSELS. 
Dr. Jeffray, Professor of Anatomy in the University of Glas- 
gow, is reported to have made an important discovery of a new 
mode of propelling vessels of any description by steam. The prin- 
ciple of the invention has not as yet been made public; but its 
results, if we may give credit to the anticipations in the Glasgow 
Courier, in which it has been announced, are altogether mar- 
velous. 
> 
MARINE BAROMETER. 
A correspondent suggests to instrument-makers the propriety 
of having a small work or treatise published, ‘to accompany the 
Marine Barometer, with a few concise rules and observations for 
the management of that instrument so useful to navigators who 
have not access to the bulky and expensive works and Encyclo- 
pdias in which it appears such rules and observations are only 
to be found, and without which the instrument in question is 
useless, DIS- 
