1820.] Memoirs of the Literary Sodeti/ of Manchester. 207 



put into fresh water and preserved for the process of tinning ; 

 for it lias been found that they will not rust in pure water though 

 kept' in it for a twelvemonth. 



An iron pot is nearly filled with a mixture of block and grain 

 tin in a melted state ; and a quantity of tallow or grease suffi- 

 cient, when melted, to cover the fluid metal to the thickness of 

 four inches is put to it. The tin is kept as hot as it can be with- 

 out inflaming the tallow on its surface. Another pot fixed by the 

 side of the tm pot is filled with grease, into which the plates ar« 

 put, and allowed to remain an hour before they are dipped into 

 the tin. They are then dipped into the tin pot in a vertical posi- 

 tion : 340 plates are usually put in at once ; and that they may 

 be thoroughly tinned, they usually remahi in it an hour and a 

 half. They are then taken out, and laid upon an iron grating to 

 allow the surplus tin to drain from them. But as too much 

 tin always adheres, this excess is removed by a subsequent 

 process called iv/ts/iiiig. 



A vessel, called the 7iiash pot, is nearly filled with the best 

 grain tin in a melted state. Into this vessel the plates are put. 

 This mass of hot metal soon melts all the loose tin on the surface 

 of the plates, which so deteriorates the grain tin that after t»0 or 

 70 boxes (a box is 22o plates) have been washed in it, the quan- 

 tity of a block (three cwt.) is usually taken out, which is 

 replaced by a fresh block of grain tin. When a plate is taken 

 out, it is brushed first on one side, ;md then on the other, by a 

 brush of hemp of a peculiar kind. It is then dipped once more 

 into the wash-pot. it is then plunged into a pot filled with 

 melted tallow, the temperature of which is carefully adjusted to 

 the thickness of the plates. Here the excess of tin runs oft", and 

 is collected in a wire at the bottom of the plate. From the 

 grease-pot the plates ore removed into another empty pot to 

 cool, and when they are cold enough to handle, a boy, called the 

 list boy, takes them and dips them one by one into a pot contain- 

 ing a little melted tin in its bottom. When the wire of t n is 

 melted, the boy takes out the plate, and gives it a smart blow 

 with a thin stick, which disengages the wire of superfluous 

 metal, and this falling off leaves only a faint stripe in the place 

 where it was attached. Nothing now remains but to clean the 

 plates from tallow. This is done by means of bran. They are 

 then put into wooden or iron boxes made exactly to tit them, and 

 are ready for sale. 



XX. T/ie Laws of Statical Erjiii/ihriam aini/i/ficaUi/ investi- 

 gated. By Mr. John Gough. — This ingenious and valuable poper 

 is of a nature not to admit of abridgment. I am, therefore 

 un ler the necessity of referring the reader to the volume itself, 

 assuring him that it will repay his trouble if he will give it a careful 

 perusal. 



XX (. Experiments on the Gas from Coal, chi^fli/ with a View 

 to its practical Application. By William Henry, M!D. F.R.S.&c. 



