Potash in Sea Water.—Salt.—Iron Boat. 371 
to be calcined in the drying oven until the sulphur is dissi- 
pated and then transported into the pots for fusion. It gives 
a superb gone a General de Sciences de Physique 
Brussels, May, 1820. 
6. Portable Gas Lamps. 
These have been contrived by David Gordon of Edin- 
burgh, and it is probable they will become quite common in 
private families. 
They and made of strong soppess either spherical or cy]- 
indrical, with hemispherical end’ The gas from coal or 
oil is foreed into them m by a edits nsing pump, and is ail 
charged through a stop cock to the burn rese 
six inches diameter and nine inches high; filled with oni, 
condensed by twenty-five atmospheres will burn six hours, 
and afford a light equal to five candles of six to the pound. 
If the gas be obtained from oil, such a lamp will burn 
twelve set A sphere twelve inches in diameter will con- 
tain sufficient gas for two argand lamps, equal to twelve 
candles, burning six hours with coal gas or twelve hours with 
gas from oil. Sue ch |, amps: © an be filled with very. jittle ex- 
roe 
q: Potash é in Sea Water. 
Dr. Wollaston has sabortainctl the existence of potash i in 
sea water. It is in the state of sulphate and constitutes rath- 
er less than sas part of the water.— 
8. Salt. 
Pheulopees salt mines and salt springs os annu- 
anys as nearly as the estimate can be made, from twenty-five 
er millions of hundred weight of salt. Iden. 
as Tron Boat. : ce 
boston the Forth ‘of Clyde seats se 
"The iron passage 
structed under the direction of Henry Creighton, Esq. for- 
merly of Soho, bas an extreme length of sixty feet, beam 
