The reproductive spores are formed in embedded flesh-shaped receptacles (perithecia) and scattered after the leaves have fallen. The spots are not often so numerous as to do much harm to the leaves, but where the disease is serious diseased leaves should be collected and burned. Sloes and bird cherries should be removed from the neighbourhood of plum-trees, as the various disease-producing insects and fungi live also on these species. The branches are sometimes attacked by weevils (Rhyncites) and the larvae of various moths, and saw-flies (chiefly Erwcampa) feed on the leaves, and young branches and leaves are sometimes invaded by Aphides. Leaf-feeding beetles and larvae of moths are best got rid of by shaking the branches and collecting the insects. Slug-worms or saw-fly larvae require treatment by washing with soapsuds, tobacco and lime-water or hellebore solution, and Aphides by syringing from below and removing all surplus young twigs.
(After Sadebeck From Strasburger's
Lehrbuch der Botanik, by permission
of Gustav Fischer)
Taphrina Pruni—Transverse
section through the epidermis
of an infected plum. Four
ripe asci, a1, a2, with eight
spores a3, a4, with yeast-like
conidia abstracted from the
spores.
st, Stalk-cells of the asci
m, Filaments of the mycelium
cut transversely.
cut, Cuticle
ep, Epidermis.
PLUMBAGO (from Lat. plumbum, lead), a name frequently applied to graphite (q.v.), in allusion to its remote resemblance to lead, whence it is popularly called "black-lead." It was formerly held in repute in medicine, but is now regarded as having no medicinal properties of any value.
PLUMBAGO DRAWINGS. What we should now speak of as pencil drawings were in the 17th and 18th centuries usually known as drawings "in plumbago," and there is a group of artists whose work is remarkable for their exquisite portraits drawn with finely pointed pieces of graphite and upon vellum. In some books of reference they are grouped as engravers, and as such Horace Walpole describes several of them. There is no doubt that many of their line pencil drawings were prepared for the purpose of engraving, but this is not likely to have been the case with all, and we have evidence of certain commissions executed, by Forster for example, when the portrait was not required for the preparation of a plate. One of the earliest of this group of workers was Simon Van de Pass (1595?–1647), and in all probability his pencil drawings were either for reproduction on silver tablets or counters or for engraved plates. A very few pencil portraits by Abraham Blooteling, the Dutch engraver, have been preserved, which appear to have been first sketches, from which plates were afterwards engraved. They are of exceedingly delicate workmanship, and one in the present writer's collection is signed and dated. By David Loggan (1635–1700), a pupil of Van de Pass, there also remain a few portraits, as a rule drawn on vellum and executed with the utmost dexterity and with marvellous minuteness, the lines expressing the intricacies of a lace ruffle or the curls of a wig being perfectly rendered. It is evident that these were not always prepared for engraving, because there is one representing Charles II, set in a beautiful gold snuff box, which was given by the king to the duchess of Portsmouth and now belongs to the duke of Richmond, and a similar portrait of Cromwell in the possession of Lord Verulam, while several others belong to Lord Caledon, and there are no engravings corresponding to these. On the other hand, a large drawing by Loggan in the writer's collection, representing Charles II, is the sketch for the finished engraving and bears a declaration to that effect. An artist who is better known to the general collector is William Faithorne (1616–1691) He was the pupil of Sir Robert Peake, the engraver, but derived much of his skill from the time he spent with Nanteuil, whose involved minute style he closely followed, triumphing over technical difficulties with great success. There are important drawings by him in the Bodleian, at Welbeck Abbey and at Montagu House, and two fine portraits in the British Museum. Thomas Forster (fl. 1695–1712) was one of the greatest draughtsmen in this particular form of portraiture. His drawings are both on vellum and on paper, as a rule on vellum. Of the details of his life very little is known. He engraved a few prints, but they are of the utmost rarity. His finest portraits are executed with very great refinement and delicacy, the modelling of the face being quite wonderful. It is in fact one of the marvels of this type of portraiture how such exquisite lines could have been drawn with the roughly cut pieces of graphite which were at the disposal of the artists. In some instances in Forster's work the lines representing the modelling of the face are so line as to be quite indistinguishable without the aid of a glass. His work can be studied at Welbeck Abbey, in the Holburne Museum at Bath, in the Victoria and Albert Museum and elsewhere. Two other Englishmen should be referred to, Robert and George White, father and son. The former (1645–1704) was a pupil of Loggan and a prolific engraver, and most of his drawings, executed on vellum, were for the purpose of engraving. George White (c. 1684–1732) was taught by his father, and finished some of his father's plates. His own pencil drawings are of even finer execution than those of Robert White. These three men, Forster and the two Whites, carefully signed their drawings and dated them. By Robert White there are remarkable portraits of Bunyan and Sir Matthew Hale in the British Museum, and his own portrait at Welbeck; and by him and his son there are other drawings in private collections, depicting Sir Godfrey Kneller, Archbishop Tennyson and others. The two Fabers (1660?–1721 and 1695?–1756) were from Holland, the elder having been born at the Hague, as he himself states on his portrait which was in Vertue's collection. In addition to the portraits these two men usually added beautiful drawn inscriptions, often found within circles around the portraits and occasionally extending to many lines below them. The son was the greater artist and a famous mezzotinter. The portrait painter Jonathan Richardson (1665–1745) executed many fine drawings in pencil, examples of which can be seen in the British Museum. One of the best of these plumbago draughtsmen was a Scotsman, whose work is of the utmost rarity, David Paton, who worked in 1670. The chief of his drawings belong to the earl of Dysart and are at Ham House, and two examples of his portraiture are in the possession of the Dalzell family. Of Paton's history nothing is known save that he was a Catholic who worked for more than one Dominican house, a devoted adherent of the Stuart cause, and was attached to the court of Charles II., when the king was in Scotland. At that time he drew his remarkable portrait of the king now at Ham House. There are drawings of the same character as his, the work of George Glover (d. 1618) and Thomas Cecill (fl. 1630), but they are of extraordinary rarity and were evidently first studies for engravings. Of Glover's work the only signed example known is in the writer's collection. A Swiss artist, Joseph Werner (b. 1637) or Waerner, drew well in pencil, adopting brown paper as the material upon which his best drawings were done, and in some cases heightening them with touches of white paint. The most notable of his portraits is one which is in the collection at Welbeck Abbey.
The earlier miniature painters also drew in this manner, notably Hilliard in preparing designs for jewels and seals, and Isaac and Peter Oliver in portraits By Isaac Oliver there is a fine drawing in Lord Derby's collection; and one by Peter, a marvellous likeness of Sir Bevil Grenville, in that of the writer. The later men, Hone, Grimaldi, Lens and Downman, also drew finely in plumbago. Other notable exponents of this delightful art were Thomas Worlidge (1700–1766), F. Steele (c. 1714), W. Robins (c. 1730), G. A. Wolffgang (1692–1775), George Vertue the engraver (1684–1756), Johann Zoffany (1733–1810), and the Swede, Charles Bancks (c. 1748), who resided in England for some years. (G. C. W.)
PLUMBING, properly working in lead (Lat. plumbum), now a term embracing all work not only in lead, but also in tin, zinc and other metals, connected with the installation, fitting, repairing, soldering, &c., of pipes for water, gas, drainage, on cisterns, roofs and the like in any building, i.e. the general work of a plumber. (See Building and Sewerage.)
