Crayon, an implement for drawing made from clay, chalk, plumbago, dry colour, and wax.
While experimenting on an underwater cable for the automatic telegraph, he found that the electrical resistance and conductivity of carbon (then called plumbago) varied according to the pressure it was under.
Wax Lyrical & Fired Earth Earl Grey & Vetivert: £34.99, ocado.com A collaboration between Brit brands Wax Lyrical and Fired Earth, the aniseed, lemon and spearmint essential oils in this give it a fresh scent, and the grey-hued glass holder, inspired by Fired Earth's Plumbago paint, makes it an elegant gift.
Yards are gaudy with plumbago, the circular driveways enclosed by wrought-iron fences.
There is also a small terrace overlooking grounds landscaped with flame trees, plumbago, palms, ficus and ixora, among other plants.
There is a vine-festooned terrace for sultry summer days, while a further series of terraces have been planted with hibiscus, oleander, palm, jasmine, plumbago and cactus.
Employees bustle from the house past a fountain filled with an exotic carrotwood tree and into the office; Hope's white German shepherds, Sno'el and Snowjob, Jr., prowl ten-foot-high hedges of blue-flowering plumbago which extend around the property and shut out the flat, blistering banality of the Valley streets.
Awe-inspiring clouds of light blue plumbago climb one trellised wall.
The sap of Plumbago europeae (leadwort) is irritating and caustic, as are the juices of other Plumbago species, for example, P. indica (or P. rosea) and P. scandens, which are grown for their rose and white or blue flowers, respectively.
The active principle extracted from Plumbago roots, used in several medicinal drugs, is a yellow pigment called plumbagin.
They call it Plumbago, which isn't the catchiest of names (it's named after a flower, but sounds more like something you'd find in Saga magazine), though it does taste seductively of plums.
