172 On extending the Uſe of Tinned Iron.[Sept-

The arrangements which would enable the tinner to confer durability on the works ol the forge, do not ſeem complicated. A moderate ſtock of block-tin, and a furnate of no vaſt dimen- fions, are all the reguiſites beſides aquafortis and burnt greaſe, The profits on this, as in all branches of a new trade, would, at firſt, be rather high, and the applications from the neigh= bouring blackſmith’s cuſtomers would ſoon become numerous. A ſtatéd day in the week, or fortnight, would be ſettled for the operation, and public convenience and national benefit would (as uſual) extend together. The moſt obvious utility of my propoſal is in ſhipping, eſpecially in ſmall’ veſſels, clench or clinker built, in which the uſe of tinned nails in the planking would more than double the duration of the fabric; and as the ſuperior cheapneſs and lightneſs of thoſe veſſels cauſe many to be built at preſent, in deſpite of their early frailty, no. ſmall proft would reſult from this eaſy expedient. The chain-plates, dead-eyes, all the iron aloft, in every veſſel, might thus be guaráed from the deleterious effes of the conſtant moiſture of the ſea air, and a confiderable addition to the ſafety of navi-

ators would enſue.

I ſhall conclude with ſome imperfedt hints at the experiments neceſary to elucidate(in a regular manner) the hiſtory of the properties of. tinned-jron. 1. The dipping to be experimented in various known temperatures. 2. To be repeated twice, thrice,- or oftener, on various pieces of iron-plate. 3. The quantity of tin adhering each time to be carefully noted. 4. Expoſure of tinned-iron to marine acids, and other mordants. 5. Calculation to be made in what ratio of time theſe mordants 2, compared with common air or water. 6. Whether the ſpecific gravity be exadly in the ratio indicated by the reſpective mixtures of the adhering metals. 7. If leſs, air muſt be incloſed in the dipping. 8. If more, the metals muſt be partly incor- porated. 9g. Whether any poſhbility of applying tin to a large body(an anchor for initance) piecemeal. 10. Relatiye coheſion of tin with copper and iron to be aſcertained.

Lhe appearánces from one experiment always induces the neceflity of other lufirative experiments; therefore it is ſuper- fluous to enumerate any more; in fad,‘theſe few are ſuggeſted merely to exemplify what is in point on‘this occaſion.‘The chemical reader will perceive. the fitneſs of many others at one glance. May I aſk him, whether chemiſtry be not at preſent too excluſively ſoaring in the air, while the utility of its fami- liar applications is too much negle@ted? If any chemiſt who thinks ſo, will dire& his reſearches to the inveſtigation above recommended, he may perhaps attaia the more ſolid glory of being recorded as an undiſputed and immediate bi: aes tao mankind.-