Methods of making Seap of F'ljh. 1 1 3 



Houfe, when he detailed the value of the fuppofed improvetnent in fuch ftrong terms, that aix 

 order was given by the Lords of Trade and Plantations to have the whole determined by a ■ 

 flcilful manufadurer, in the neighbourhood of fome fifliing ftation ; and, in compliance with 

 this order, the Honourable tlie Board of Truftees, at Edinburgh, requefted my father to make 

 the neceflary trials, and report for their fatisfadtion. Thefe experiments were made as foon 

 as ciccumftances would permit; and the refult has been lately laid iefore the board. As this • 

 report contains a fatisfai^ory feries of experiments, I will now lay before the public a few of 

 them, with the view of fetting this fuppofed improvement in a proper point of view. 



Previous to this, I fliall mention, in as few words as poffible, the procefles followed by 

 Sir John Dalrymple in making bard and foft foaps *. 



To make Soft Soap. The lifli are firrt to be well wafhed in water, to free them from blood, 

 &c. and are then to be thrown into a boiling folution of cauftic potafli, in the proportion of 

 from fix to ten parts of fi(h to ten of alkali. The ftfli being diflblved, tallow is then to be 

 added in the proportion of one part to eight of fifh. Thefe being boiled together for fomc 

 time, turpentine is added in the proportion of one part to fixteen of foap ; afterwards, a 36th 

 part of palm-oil is added, to give the foap a better colour. The foap being finiflied, it is to be 

 fpread about two inches thick in a cool place, and kept there for a month before being ufed ; 

 durmg this time, it muft be turned every two or three days with fiiovels or hoes. 



To make Hard Soap. Having drffolved a certain quantity of fifh in cauftic vegetable 

 alkali, an equal quantity of tallow is to be added, and to be continued boiling, until they are 

 completely united. The yeflel is then allowed to cool, and mineral alkali, or mineral and vc-* 

 getable alkali, and rofin are to be added : the alkaline ley in the proportion of five parts to 

 twenty of fifh and tallow. The whole is then to be boiled, and in an hour after the ftrongeft 

 waftc ley is to be added in the proportion of two parts in weight to 25 parts. The whole is 

 then to be boiled until the alkali has united with the vegetable and animal matters. The ley is 

 now to be pumped ofF, and cauftic mineral alkali added, in the proportion of three parts ih 

 weight to 25 parts ; and the whole is to be boiled, until a good foap is formed : laftly, the foap 

 is to be melted in water, and caft into frames. 



We need not ftop to examine the procefles here detailed, as they muft appear, from what 

 has been already ftated with regard to foap-making, to be very incorreft. 



As the report given to the Board of Truftees contains a long feries of experiments, it would' 

 occupy too much room to infert them at full length ; I {hall, therefore, only abftrad thofe whicll 

 appear to be the moft important. 



■ -•I 

 Hard Soap from Ftjh, i^c. 



EXPERIMEWT I. 



Thofc 



