in Sulphuric Acid of different Densities. 163 



Since I concluded these experiments it occurred to me, 

 that it might be useful to some manufacturers to know the 

 quantity of acid per cent, in diluted acid of any given 

 strength ; I have therefore calculated the quantity in each, 

 and annexed it. The column of ounces and drachms is 

 added for the use of those who are accustomed to this mode 

 of reckoning, and also for those who are not conversant 

 with the usual method of stating specific gravities; and is 

 calculated on ihe supposition of the wine pint holding ex- 

 actly sixteen ounces avoirdupois of pure water*. 



The sulphuric acid which is consumed in these kingdoms 

 amounts I believe to upwards of three thousand tons an- 

 nually ; the greater part of which is used in a state of di- 

 lution. For the purposes of dissolving iron or zinc, it 

 should be diluted with at least five or six times its weight 

 of water. Sulphuric acid is consumed in large quantities 

 by bleachers, for making the oxymuriate of lime, and these 

 people alwavs use it in a state of dilution. The calico 

 printers also expend large sums in the purchase of this acid, 

 which they use in various stales of dilution, for making 

 what they call sours. 



To these, and other manufacturers, this Table will be of 

 use, not only in assisting them in the formation of acid of 

 any given strength, but it will enable them at any time to 

 ascertain whether their servants have observed due care in 

 making the different preparations ; which is a matter of 

 great moment — for it often happens, that for want of this 

 the printer and manufacturer suffer great loss, and the 

 goods sustain an irreparable injury. 



I need scarcely add that the oil of vitriol-makers them- 

 selves, may also derive great benefit from attending to this 

 Table. 



I am, sir, yours, &c. 



Goswell-street Chemical Works, ' SamUEL PaRKES. 



London, Sept. 2, 1812. 



• It 13 a convenient way of measuring, to have a glass bottle with a nar- 

 row neck, holding rather more than a pint of water, with a mark on the 

 stem exactly at the place to which ttie v/ater a-^cends when it contains ex- 

 actly 16 ounces avoirdupois of th.it fluid. It was formerly undei stood 

 that the standard wine pint wai the ex.ict measure of 16 ounces of pure 

 water; but some cTpcrimeoLs made iu the year 1688, before the Lord Mayor 

 and the Board ol Excii^e, decided, that the .sealed wine gallon of Guildliall 

 contains only 2'.^4 cubic inches, though by the fifth of Queen Ann, chap vii. 

 § 7, it ik called 231 inches This decision makes tlie wine pint to hold 

 only 970 of an avoirdupois pound of water; but as it is generally thouglit 

 right, fur all common purposes still to consider it of the capacity ui 15 

 oujice« avvirdupau, i have taken it at that, iii this ijistance. 



L 8 A Table 



