460 PHILOSOPHICAL TRANSACTIONS. [aNNO I678. 



it with sea- water, which cannot be discovered by weight : they try it by putting 

 it to some of the boiling liquor : for if the urine be good, it will work like yest 

 put to beer or ale ; but if mixed, it will stir no more than so much water. It 

 is observed, that the best urine is that which comes from poor labouring people, 

 who drink but little strong liquor.* 



The boiling pans are made of lead, Q feet long, 5 feet broad, and 2^ deep, 

 set upon iron plates, about 2 inches thick ; which pans are commonly new cast, 

 and the plates repaired 5 times in 2 years. — -When the work is begun, and 

 alum once made, then they save the liquor which comes from the alum, or 

 wherein the alum shoots, which they call mothers. With this they till two 

 thirds of the boilers, and put in one third part of fresh liquor, which comes 

 from the pits. Being thus filled up with cold liquor, the fires having never 

 been drawn out, they will boil again in less than 2 hours time ; and in every 

 two hours the liquor will waste 4 inches, and then the boilers are filled up again 

 with green liquor.-— The liquor, if good, will in boiling seem greasy at the top : 

 if nitrous it will be thick, muddy, and red.-J- In boiling 24 hours, it will be 36 

 pounds weight ; then about a hogshead of the lees of kelp is put into the boiler 

 of about two penny weight, which will reduce the whole boiler to about 27 

 pounds weight. — If the liquor be good, as soon as the lees of kelp are put into 

 the boiler, they work like yest put to beer : but if the lijquor in the boiler be 

 nitrous, the kelp-lees will stir it but very little ; and in that case they put in the 

 more and stronger lees. — Presently after the kelp lees are put into the boiler, 

 all the liquor is drawn into a settler as large as the boiler, made of lead, in which 

 it stands about two hours; in which time most of the nitre and slam sink to the 

 bottom. — ^This separation is made by means of the kelp-lees. For when the 

 whole boiler consists of green liquor drawn from the pits, it is of power strong 

 enough to cast off the slam and nitre : but when mothers are used, the kelp- 

 lees are needful to make the said separation. — ^Then the liquor is scooped out 

 of the settler into a cooler, made of deal-boards, and rammed with clay. Into 

 this is put 20 gallons or more of urine, more or less, according to the goodness 

 of the liquor ; for if the liquor be red,-!" and consequently nitrous, the more 

 urine is required. In temperate weather the liquor stands 4 days in the cooler. 

 The second day the alum begins to strike, gather and harden about the sides, 

 and at the bottom of the cooler. If the liquor should stand in the cooler above 

 4 days, they say it would turn to copperas — The use of urine is both to cast off 

 the slam, and to keep the kelp-lees from hardening the alum too much. In hot 

 weather the liquors will be a day longer in cooling, and the alum in gathering,- 



* This alum consists of 4« ingredients. + This redness is owing not to nitre but iron. 



