i805.] 



Proceedings of learned Societia. 



47 



purity. The Doflor next ciefciibes a ma- 

 chin." for cleanling manganelt;, which will 

 leiTen the exp^-nce ot manual labour, and 

 vhich may be applied to a varitty of other 

 piirpolei in the vvalhino and cleaning way, 

 particularly in cleaning feathers for bcd- 

 dino;. 



The gold medal was adjud^ed^ to Mr. 

 Matthew Gkugson, of Liverpool, for 

 the great attsniion which he h^s piid to 

 render uieful articles remaining after ihe 

 calamity "f public fires. To thefe invel- 

 tigatinns he was led bvthe great fire which 

 happened in Liverpool in ths fumnier ot 

 l!Jox. From the ruins of tlie wsiehoutes 

 he collei^ed burnt lugar, wheat, rice, 

 fljur aiiJ cottou. The damaged articles 

 of every defcription I'old for liit'e m re 

 than 13,000!. but he conceives, that had 

 ihe plan been recurred to which he i.as- 

 fince aiiopted, a faying of 44.,oocl. n;ighc 

 have been m^.ie on the artiale of grain 

 only, and he thinks that nearly as much 

 might have been giined upon rice, fugar, 

 inolafTcs, cotton, coffee, hc:iip,&c. 



The proceifes which he his tried and 

 which coinpleiely aiifwer, are as follow- : 

 I, The burnt fugar was reduced to a fine 

 powder, arid maJe into a wattr-coKrur 

 paint. It anfwered alfo rs a varni/li 

 ground j an oil colour ; jind a printir.g- 

 ink. — I. Burnt whrat anlwered the fame 

 purpofes. — '^d. Tl;*: iiurrit American fine 

 floi-.r he fuccefsfuliy inanu'sftured into 

 pafte. To the above named purpofes, 

 Mr. G. is Hire the burnt niateriais aie 

 applicable, and may be converted v/iih the 

 greatefteafe- 



" That corn," fays he, '* when charred 

 is incorruptible, is a faft that wa.s kn-.iwn 

 to the ancients ; and if i"j tivie tan he lit- 

 tle doubt but the colour will be durable. 

 It is not in my power to fay wht:ther it 

 may be ufed for dyeinp; ; but I iinj in- 

 clined to think that the CliinJe make In- 

 dian ink ot rice, or foiue vesetiibleblac'c.'" 

 The importance of this difcovcry, it it 

 anfwe.'s the fanguine expeftations of Mr. 

 Gregfoii, eannot be doubted, fince carg es 

 of grain and flour rendered ahuoii uirlefs 

 in lopg voyages by heiting,' may be con- 

 verted to thefe ufctul piiLi^)IVs, anil thus 

 their value greatly incre^tl. and the dry- 

 ing c|iialjty will rccommt-nd their ufe, as 

 lamp-black is much objeiled to on account 

 of its fl>wnef8 in drying. 



Dr. HowisON tranfmitted to this fn- 

 ciety a barrel of the preparation of tan, 

 which weighed S4-lh. with documents to 



Erove that 1 lolbs. had been prepared by 

 im, a: the rate of about fjxteen fhillings 

 |wr cvrt. but which in large quantitkt 



miaht be manufactured al the rate of ten 

 fnillmgs per cwt. 



This tanning prlnc'ple wns oit railed 

 from Mangrove bark, ard the apparatus 

 ufed for the puvpnfe ccnfuied o( four wood- 

 en cilfcrns, relembling coolers, fitted with 

 cocks, and lb elevated one above another, 

 as to admit of an) liquid, contained in the 

 higher ciltern, running off into that immc- 

 diarely under if. 



Dr. H. divided .voolbs. of the bark 

 (broke into fmall pieces.) into three equ?\l 

 parts, one of wliich was t'^'rown into each 

 of the three higlirft ciftenis. To the bark 

 in the UP) ermoii ciltern he added toogal- 

 lo.'is of rain water, which were allowed to 

 iC'Tia'n t*clve hours. The infufion was 

 then drawn off ioto the I'econd, and, after 

 ftai. ding for alimilar period, into the third, 

 and hiily into the fourth, wh ch had beet> 

 kept empty to receive the faturated infu- 

 fion, to be farther concentrated by evapo. 

 ration. The cocks belonging to each cif- 

 tern, v.-hen once 'urncd, were left open to. 

 admic of the infufion draining ofF corr.- 

 plettly. 



The whr)le liquid coUefled into the 

 evaporating ciiUiu was expofed to the 

 heat of the fun, until concentrated fo as 

 to nfemble thick iV-nip, at which time the 

 lixivium was reduced to about eight gal- 

 lons. It w's then drawn efl" clear fi am its 

 piecipitate into a copper boiler, in whicli 

 it was boiled on a flow fiie, and keptflir- 

 ring, until the extiafl acquired a confif- 

 tcr.ce that would juft admit of its being 

 poured into the barrel ; in this I'.ate it had 

 tile appearance of pitch. 



For this communication, which may 

 prove of great value in commerce, the 

 Society of Alts adjudged Dr. Howifon 

 their gold. medal. The Doflcr has made 

 a fruiilar extrafit from Myrab-Iar.s, which 

 is likely to be extremely ufe'ui both for 

 tannintr and dying. 



Dr. Huwifon communicated the follow, 

 ing procefs for ^printing on cotton clo h » 

 ptrmaneiU fubftantive bl?ck colour : Take 

 fume Malacca nuts which may be had in 

 Bengd at the r.^te of two (hidings per 

 cwt. boil them in water in clofe earthen 

 Velills, with the leaves if the tree; during^ 

 the boiling a wh'tifh (ubJtance, formed 

 from th; mucilage anii oil ofihenuls, 

 lil'estothe ftirlace, which whitilh fcum 

 mull he taken oft' and pielVrved. Tl;c 

 cloth intcndeil to he Llack mult be printed 

 wi'h ti.is fruiii and then dried ; it is then 

 to be paffed through lime-water, which 

 ciiajiges the pri"ted figures on it 10 a full 

 and permanent t>Uck. 



l\\i. MACHt.ictii.AN, of Calcutta, has 

 communicated 



