Browsing named entities in Knight's Mechanical Encyclopedia (ed. Knight). You can also browse the collection for Hertfordshire (United Kingdom) or search for Hertfordshire (United Kingdom) in all documents.

Your search returned 3 results in 3 document sections:

Knight's Mechanical Encyclopedia (ed. Knight), D. (search)
as visible at Belfast, a distance of nearly seventy miles, in a direct line. Subsequently, Colonel Colby made a lime-light signal visible from Antrim, in Ireland, to Ben Lomnd, in Scotland, a distance of ninetyfive miles in a straight line. It is stated that, intensified by a parabolic reflector, it has been observed at a distance of 112 miles. It is understood that the first application in practice was when it was required to see Leith Hill, in Surry, from Berkhampstead Tower, in Hertfordshire. The practical application was described in two papers published in the Philosophical Transactions of 1826 and 1831. The apparatus consists of a lamp which admits oxygen and hydrogen gas at the respective apertures o h. The gases come from separate holders, and do not mix till they reach the chamber c. Here they pass through several thicknesses of wire-gauze, which prevent explosion by the reflex action of the flame, and then issue at two points, being projected upon the ball b, wh
Knight's Mechanical Encyclopedia (ed. Knight), R. (search)
nd-slips and watercourses. Highways were first made public in many parts of England by the Romans. In the time of Edward I. they were ordered to be widened and cleared of trees within 200 feet of the road, for the prevention of robberies. Toll was granted on one in London in 1346. The parishes were made answerable for their condition in 1553. Toll-gates were erected in 1663. In the sixteenth year of the reign of the frivolous Charles II. a turnpike road was established through Hertfordshire, Cambridgeshire, and Huntingdonshire. The Simplon road from Geneva to Milan, built by Napoleon, cost the French government 17,000,000 livres ($3,250,000). MacAdam says: The measure of substituting pavements for convenient and useful roads is a kind of desperate remedy, to which ignorance has had recourse. The mode of road-making with broken stone, before MacAdam, was to make a foundation of large stone, on them place stones of a medium size, and finish off with the smallest. Ma
Knight's Mechanical Encyclopedia (ed. Knight), S. (search)
affording a greatly increased supply of moisture, which was said to have the effect of causing the plants to vegetate luxuriantly and of destroying insects. In 1799, Boulton and Watt constructed a heating apparatus, in Lee's factory, Manchester, in which the steam was conducted through cast-iron pipes, which also served as supports to the floor. See also heating apparatus, pages 1088-1091. One of the first buildings heated by steam is said to have been a silk-mill at Waterford, in Hertfordshire. It was 106 × 33 feet. 4 stories high. A furnace was built on the outside, and from the boiler rose a stand-pipe which had branches suspended from the ceiling of each story. The lower story had a pipe 5 inches in diameter; the 2d and 3d stories, pipes of 4 inches; the 4th story, one of 3 inches. The hight of the stories decreased upwardly. The pipes had a slight inclination to allow the water of condensation to run off, and valves at each story governed the admission of steam to the