October 7,1871.] 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
283 
deters for Stutats. 
CHEMICAL NOTES TO THE PH ARM ACOPCEIA. 
BY WILLIAM A. TILDEN, D.SC. LOND. 
DEMONSTRATOR OF PRACTICAL CHEMISTRY TO THE 
PHARMACEUTICAL SOCIETY. 
Plumbi Acetas. —Oxide of lead is dissolved in 
acetic acid, used in slight excess, and the salt made 
to crystallize by evaporating the solution. Sugar of 
lead occurs in crystalline masses, having a sweetish 
astringent taste and an acetous odour; it is soluble 
in spirit and in water. [§ The solution slightly 
reddens litmus, gives a yellow precipitate (Pbl 2 ) 
with iodide of potassium, and is precipitated white 
(PbS0 4 ) by sulphuric acid, acetic acid being set 
free.] It is hardly liable to any impurity. 
Plumbi Carbonas. —Though of small importance 
pharmaceutically, carbonate of lead occupies, as a 
pigment, a very prominent position. It is made 
largely by a process which is but httle varied in 
different countries. The principle upon which it 
depends is found in the fact that a mixture or com¬ 
pound of oxide and acetate of lead is converted by 
carbonic acid gas into a mixture of carbonate and 
neutral acetate of lead. Practically, metallic lead is 
exposed to the simultaneous action of acetic acid 
vapour, atmospheric oxygen and carbonic acid, with 
the assistance of a slightly elevated temperature. 
The carbonic acid is supplied very commonly by the 
fermentive decomposition of tan and stable manure; 
or sometimes by the combustion of coke or charcoal. 
It may fairly be supposed that the acetic acid and 
oxygen coat the metal superficially with a basic or 
oxyacetate, which, as soon as formed, is transformed 
by the carbonic acid into carbonate, and that this 
kind of action continues till the whole of the lead is 
converted. 
Wliite-lead is adulterated with chalk, sulphate of 
barium and other substances. 
[§ Tests.—Soluble with effervescence in diluted 
acetic acid without leaving any residue. The acetic 
solution, when treated with excess of sulphuretted 
hydrogen, boiled and filtered, gives no precipitate 
with oxalate of ammonia.] 
White-lead is a lrpdrate-carbonate, but varies in 
composition; it is often 2PbC0 3 , Pb(HO) 2 . 
Plumbi Iodidum, Pbl 2 .—Solutions of nitrate of 
lead and iodide of potassium are mixed together, 
and the bright yellow precipitate cohected, washed 
and dried. 
Pb (N 0 3 ) 2 + 2KI = Pbl 2 -f 2 K N 0 3 . 
Although the Pharmacopoeia directs the salts to be 
dissolved in water by the aid of heat, the solutions 
should be allowed to cool before mixing or the pre¬ 
cipitate will sometimes be too distinctly crystalline. 
Iodide of lead may readily be crystallized from boiling 
water in scales which have the lustre and appearance 
of gold. 
Plumbi Nitras, Pb(N0 3 ) 2 .—An anhydrous salt, 
crystallizing in regular octahedra, which are usually 
opaque, and prepared by dissolving lead,— 
3Pb + 8HN0 3 = 3Pb (N 0 3 ) 2 + 4H 2 0 + 2NO, 
or its carbonate or oxide in dilute nitric acid. 
PbO + 2 HN0 3 = Pb (N 0^2 + H 2 0. 
The solution gives the usual reactions of lead com¬ 
pounds and of nitrates. 
DETERMINATION AND CHARACTERISTICS OF 
CITRIC ACID. 
BY H. KAMMEREB. 
Soluble citrates mixed with acetate of baryta, either 
hot or cold, produce a white amorphous precipitate 
being 3 BaO, 2 C^H^Ojj, 3 Ho, + 1-i aq. 
If, after precipitation, an excess of acetate of baryta be 
added, and the mixture heated in a water-bath, the pre¬ 
cipitate becomes heavy and granular, it loses one-half of 
its water of crystallization, and has now the composition 
3 BaO, 2 C I2 H 5 O n , 3 Ho + 7 aq. 
The presence of other organic acids does not interfere; 
the granular salt is absolutely insoluble in water, and 
citric acid may thus be easily determined. If the solu¬ 
tions are very dilute they must be concentrated by 
evaporation, after additions of acetate of baryta, or the 
precipitate will consist of crystalline needles containing 
only 5 aq.— Zcitschr. fur Analyt. Chemie, viii. p. 298. 
Inspection of "Weights and Measures. —Under 
the Act 5 & 6 William IV. all persons are liable to 
have their weights and measures inspected who are pro¬ 
prietors of any “ shop, store, warehouse, stall, yard or 
place whatsoever, wherein goods are exposed or kept for 
sale, or weighed for conveyance or carriage.” A Bill 
for amending and consolidating the laws relating to 
weights and measures was prepared by the Standard 
Weights and Measures Department, and submitted to 
the consideration of the Government last session; the 
Bill, however, was not limited to consolidation with un¬ 
questioned amendments, but proposed the permissive 
introduction of the metric system, and was left among 
the “ good intentions ” of the Session. The Warden of 
the Standards observes that it deserves consideration 
whether the class of persons liable to inspection of their 
weights and measures should continue to be defined in 
the above terms; these are now construed as not in¬ 
cluding wholesale dealers, and it might be a matter of 
just complaint on the part of retail dealers that, while 
they are themselves subject to the visits of inspectors of 
weights and measures, the wholesale dealers from whom 
they must buy their goods are not subject to such in¬ 
spection. The absence of authoritative instructions to 
the inspectors specifying more exactly the trades subject 
to inspection has led to many traders not having been 
subjected to it. For example, chemists and druggists, 
pawnbrokers, etc., using troy weights, have hardly ever 
had their weights inspected. x\n attempt has been made 
by the department to ascertain, with the aid of the 
census returns of 1861, the number and description of 
traders, manufacturers, etc., using weights and measures 
who are not liable to inspection under the existing law. 
A list has been made out from which it would appear 
that out of a total population of 29,000,000 in the United 
Kingdom in 1861, 1,333,679 persons were engaged, in 
trades subject to inspection of their weights and mea¬ 
sures, and 3,627,988 persons were engaged in trades and 
manufactures requiring the use of weights and measures 
who are not liable to inspection. Among the persons 
not liable to inspection are cotton, woollen, linen and 
silk manufacturers, tailors, blacksmiths, carpenters, 
farmers, dressmakers, coopers, cigar and tobacco manu¬ 
facturers, candlemakers, copper manufacturers, engine 
and machine makers, flannel manufacturers, felt manu¬ 
facturers, opticians, outfitters and clothes dealers, picture- 
frame makers, plated-ware manufacturers, saddlers, type¬ 
founders.— Times. 
The Lemon-tree Disease. —Her Majesty’s Consul 
at Messina reports that the disease of the lemon-tree 
continues its ravages, and nothing has yet been disco¬ 
vered to arrest its progress. Last year the oranges, but 
more particularly the lemons, were badly tainted, and a 
large proportion being unfit for shipment, were converted 
into juice or essence. 
