Ilium; Is, ischium; Pb, pubis; d.l, dorso-lumbar vertebrae; Cd, caudal vertebrae; Am, acetabulum.
The metals may be arranged in a series according to their power of displacing one another in salt solutions, thus Cs, Rb, K, Na, Mg, Al, Mn, Zn, Cd, Tl, Fe, Co, Ni, Sn, Pb, (H), Sb, Bi, As, Cu, Hg, Ag, Pd, Pt, Au.
Group IV.: C, Si, Ge, Zr, Th, tetravalent; Ti, tetravalent and hexavalent; Sn, Pb, divalent and tetravalent; Ce, trivalent and tetravalent.
Ca, Ba, Sr, Pb; Fe, Zn, Mn, Mg; Ni, Co, Cu; Ce, La, Di, Er, Y, Ca; Cu, Hg, Pb; Cd, Be, In, Zn; Tl, Pb.
LEAD, a metallic chemical element; its symbol is Pb (from the Lat.
The following analysis of blast-furnace lead of Freiberg, Saxony, is from an exceptionally impure lead: Pb =95.088, Ag = 0.470, Bi = 0.019, Cu = 0.225, As = I.
Water when absolutely pure has no action on lead, but in the presence of air the lead is quickly attacked, with formation of the hydrate, Pb(OH) 2, which is appreciably soluble in water forming an alkaline liquid.
Dilute nitric acid readily dissolves the metal, with formation of nitrate Pb(N03)2.
Pb 2 0, PbO, Pb0 2, Pb203 and Pb304.
The suboxide, Pb 2 0, is the first product of the oxidation of lead, and is also obtained as a black powder by heating lead oxalate to 300° out of contact with air.
The corresponding hydrate, Pb(OH)2, is obtained as a white crystalline precipitate by adding ammonia to a solution of lead nitrate or acetate.
It dissolves in an excess of alkali to form plumbites of the general formula Pb(OM) 2.
By dissolving red lead, Pb304, in glacial acetic acid and crystallizing the filtrate, colourless monoclinic prisms of lead tetracetate, Pb(C2H302)4, are obtained.
This salt gives the corresponding chloride and fluoride with hydrochloric and hydrofluoric acids, and the phosphate, Pb(HP04)2, with phosphoric acid.
Here compounds of divalent lead have not yet been obtained; by acting with zinc ethide on lead chloride, lead tetraethide, Pb(C 2 IH Q) 4, is obtained, with the separation of metallic lead.
A basic chloride, Pb(OH)Cl, was introduced in 1849 by Pattinson as a substitute for white lead.
Of greater practical importance is a basic carbonate, substantially 2PbCO 3 Pb(OH) 2, largely used as a white pigment under the name of "white lead."
Strong sulphuric acid dissolves it, forming an acid salt, Pb(HS04)2, which is hydrolysed by adding water, the normal sulphate being precipitated; hence the milkiness exhibited by samples of oil of vitriol on dilution.
Lead nitrate, Pb(N03)2, is obtained by dissolving the metal or oxide in aqueous nitric acid; it forms white crystals, difficultly soluble in cold water, readily in hot water and almost insoluble in strong nitric acid.
Pb(N03)OH, Pb30(OH)2(N03)2, Pb 3 02(OH)N03, &c., have been described.
The borate, Pb 2 B 6 0 1 u 4H20, is obtained as a white precipitate by adding borax to a lead salt; this on heating with strong ammonia gives PbB2044H2.
Lead acetate, Pb(C2H302)2.3H20 (called "sugar" of lead, on account of its sweetish taste), is manufactured by dissolving massicot in aqueous acetic acid.
(All the numbers are, of course, pb +qd supposed to be positive.) 27.
Represented by a point P, so chosen that the perpendicular Pa on to the side BC gives the percentage of A in the alloy, and the perpendiculars Pb and Pc give the percentages of B and C respectively.
Charpy, these lines are Pb, 325 Bi 200° 150° E" 175° FIG.
It is easy then to show that PA: PB =d: r.
Of the minerals containing gold the most important are sylvanite or graphic tellurium (Ag, Au) Tee, with 24 to 26%; calaverite, AuTe2, with 42%; nagyagite or foliate tellurium (Pb, Au)16 Sba(S, Te)24, with 5 to 9% of gold; petzite, (Ag, Au) 2 Te, and white tellurium.
Let us suppose that with constant excess of pressure, p, in the wind-chest, the amplitude produced is proportional to the pressure, so that the two tones issuing may be represented by pa sin 27-nit and pb sin 21rn 2 t.
Is then pb/(m-1) inch-tons, or to any volume B cub.
Navarrese-Aragone~e has the diphthongs Ce, ue from tonic and, and adheres more strictly to them than normal Castilian doescuende (c b m i t e rn) huey (h d 1 e), pueyo (pb di U rn), yes (e s t), yeran (h r ii n t), while Castilian says conde, hoy, poyo, es, ryan.
(a) Let AA', BB' be the axes intersecting at right angles in a point C. Take a strip of paper or rule and mark off from a point P, distances Pa and Pb equal respectively to CA and CB.
0: M n: 0,0: Pb: O, and giving oxygen with sulphuric acid, and chlorine with hydrochloric. L.
2) be the particle and PB a normal to the surface.
Further, at any one of the centres of load let PL represent the magnitude and direction of the gross load, and Pa, Pb the two resistances by which the piece to which that load is applied is supported; then wifl those three lines be respectively the diagonal and sides of a parallelogram; or, what is the same thing, they will be equal to the three sides of a triangleS and they must be in the same plane, although the sides of the polygon of resistances may be in different planes.
~ Three-dimensional Kinematics of a Rigid Body.The position of a rigid body is determined when we know the positions of three points A, B, C of it which are not colljnear, for the position of any other point P is then determined by the three distances PA, PB, PC. The nine co-ordinates (Cartesian or other) of A, B, C are subject to the three relations which express the invariability of the distances BC, CA, AB, and are therefote equivalent to six independent quantities.
36 it is seen that the line joining the points A and B is the locus of the intersection of equal tangents, for if P be any point on AB and PC and PD the tangents to the circles, then PA PB = PC 2 = PD 2, and therefore PC = PD.
Lead cyanide, Pb(NC) 2, however, does not form such a salt, and is insoluble in potassium cyanide solution.
Is m - pb 1 - (B/- 11.