It is always necessary to know exactly how much lead acetate is contained in the solutions prepared by these processes. The lead or the litharge is therefore weighed and the volume of the lead acetate solution measured. One hundred parts by weight of crystallised lead acetate are obtained from 62·54 parts of lead. Lead acetate solutions must be kept in well-covered vessels. The carbonic acid of the air will turn the liquid turbid. The turbidity may be removed by the addition of acetic acid. In the following table is given the percentage of crystallised lead acetate contained in solutions of different specific gravities:— +--------+------------+--------+------------+ |Specific|Crystallised|Specific|Crystallised| |Gravity.|Lead Acetate|Gravity.|Lead Acetate| | | per cent. | | per cent. | +--------+------------+--------+------------+ | 1·0000 | 0 | 1·1869 | 26 | | 1·0064 | 1 | 1·1955 | 27 | | 1·0127 | 2 | 1·2040 | 28 | | 1·0191 | 3 | 1·2126 | 29 | | 1·0255 | 4 | 1·2211 | 30 | | 1·0319 | 5 | 1·2303 | 31 | | 1·0386 | 6 | 1·2395 | 32 | | 1·0453 | 7 | 1·2486 | 33 | | 1·0520 | 8 | 1·2578 | 34 | | 1·0587 | 9 | 1·2669 | 35 | | 1·0654 | 10 | 1·2768 | 36 | | 1·0725 | 11 | 1·2867 | 37 | | 1·0796 | 12 | 1·2966 | 38 | | 1·0867 | 13 | 1·3064 | 39 | | 1·0939 | 14 | 1·3163 | 40 | | 1·1010 | 15 | 1·3269 | 41 | | 1·1084 | 16 | 1·3376 | 42 | | 1·1159 | 17 | 1·3482 | 43 | | 1·1234 | 18 | 1·3588 | 44 | | 1·1309 | 19 | 1·3695 | 45 | | 1·1384 | 20 | 1·3810 | 46 | | 1·1464 | 21 | 1·3925 | 47 | | 1·1544 | 22 | 1·4041 | 48 | | 1·1624 | 23 | 1·4156 | 49 | | 1·1704 | 24 | 1·4271 | 50 | | 1·1784 | 25 | —— | —— | +--------+------------+--------+------------+ =Basic Lead Acetate=, Pb(C₂H₃O₂)₂.2PbO.—This salt may be regarded as a compound of neutral lead acetate with lead oxide. It is obtained by digesting vinegar with excess of litharge or with metallic lead, and also by treating lead acetate solution with litharge so long as the latter is dissolved. In the method last given, 100 parts of sugar of lead require about 118 parts of litharge to produce a saturated solution of basic acetate. The solution of this compound is alkaline; it turns red litmus paper blue. When exposed to the air, a turbidity is quickly produced owing to the separation of lead carbonate. In one white lead process basic lead acetate is the starting point of the manufacture.