MAD

114

Mad

M.

MACHICOLATIONS, openings made through the roofsof portals to the floor above, or in the floors of projectinggalleries, for the purposes of defence, by pouring through themboiling lead, pitch, &c., upon the enemy. In the galleriesthey are formed by the parapet, or breast-work, being set outon corbels beyond the face of the wall, the spaces betweenthat open throughout are the machicolations. From its stri-king appearance, the corbelled parapet was frequently usedwhere machicolations were not required for the purposes ofdefence, and the apertures so called were omitted. Machico-lations do not appear to have been used earlier than the endof the twelfth century.

MACHINE , signifies anything used to augment or regu-late moving forces or powers ; or it is any instrument em-ployed to produce motion, in order to save either time orforce. The word is of Greek origin, and implies machine,invention, art; it is therefore properly applied to any agent, inwhich these are combined, whatever may be the strength orsolidity of the materials of which it is composed. The termmachine is, however, generally restricted to a certain class ofagents, which seem to hold a middle place between the mostsimple tools or instruments, and the more complicated andpowerful engines ; this distinction, however, has no place ina scientific point of view ; all such compound agents beinggenerally classed under the term machines, the simple partsof which they are compounded being termed MechanicalPowers.

Machines are again classed under different denominations,according to the agents by which they are put in motion, thepurposes they are intended to effect, or the art in which theyare employed, as— Electric, Hydraulic, Pneumatic , Military,Architectural, &c., Machines .

The maximum effect of machines, is the greatest effect■which can be produced by them. In all machines, workingwith a uniform motion, there is a certain velocity and a cer-tain load of resistance that yield the greatest effect, andwhich are therefore more advantageous than any other.A machine may be so heavily charged, that the motionresulting from the application of any given power will beonly sufficient to overcome it; and if any motion ensue, itwill be very trifling, and the effect small. Again, if themachine is very lightly loaded, it may give great velocity tothe load ; but, from the smallness of its quantity, the effectmay still be very considerable, consequently between thesetwo loads there must be some intermediate one that willrender the effect the greatest possible. And this is equallytrue in the application of animal strength, as in machines,at'u both have been submitted to strict mathematical investi-gation, the former being founded on numerous experimentsand observations on the best method of applying animalstrength, and the measure of it when applied in differentdirections.

MADERNO, CHARLES, an eminent Italian architect,born at Bissona, in Lombardy , in 1556. He went at a veryearly age to Rome , where his uncle, Dominico Fontana, wasa, i,'if.t time in full employment as an architect. His geniusfor sculpture became manifest, and he was placed with anartist in that branch of the fine arts. His progress in model-ling was such as led his uncle to confide to him the manage-ment of some buildings then in hand, which he executed with

so much skill, that he was advised to devote himself entiretyto architecture. On the death of Sixtus V. , Madernoappointed to design and execute the magnificent tomb for l” 3interment. The public works which were carried on und® rClement VIII . were chiefly committed to the care of t' 113artist, and so high was his reputation in the succeeding P° n 'tificate, that, on the succession of Paul V. in 1605, he w® 9appointed to finish the building of St. Peter’s; his pi*” 3being preferred to those of eight competitors, and the vvorswas placed under his direction. He was afterwards empl°) reuupon the pontifical palace on the Quirinal mount. Anotherwork, for which he is celebrated, was the raising a fine flute^column found in the ruins of the Temple of Peace,placing it on a marble pedestal in the square of St. Ma rl *Maggiore. His genius was by no means confined to archtecture, he was sent by the pope on a commission to exam'®®the ports of the Ecclesiastical States, and afterwards survey® 0the lake of Perugia , and surrounding country, in order t®divert the inundations of the river Chiana. He was consul!®upon most of the great edifices undertaken in his time 1,1France and Spain , as well as in the principal towns of Iwtyj,His last work of consequence was the Barberini palace 0Urban VIII., which he did not live to complete. He m e £of the stone in 1629, when he had attained to the age 0seventy-three. He had seen ten popes, by most of whohe had been regarded with favour. .

MAGAZINE, Powder, a building constructed for keep 10 ®large quantities of powder. These magazines were fornte r ;towers erected in the town-walls ; but many inconveniei*®,^attending this situation of them, they are now placed 1different parts of the town. They were at first construct^with Gothic arches ; but M. Vauban, finding these too we® ^constructed them in a semicircular form, of the follow* 11 ®dimensions : 60 feet long within, and 25 broad ; the fou**, ^tion 8 or 9 feet thick ; and 8 feet high from the foundat*®to the spring of the arch ; the floor about two feet fromground, to prevent damp ; and consequently six feet forheight of the story. . t

The thinnest part, or haunch of the arch, is three 1thick, and the arch made of four lesser ones one overother, the outside of the whole terminating in a slope to *°the roof; from the highest part of the arch to the rid^ 0 ^eight feet, which makes the angle somewhat greater t*ninety degrees ; the two wings, or gable ends, are fourthick, raised a little higher than the roof, as is customary ^other buildings : the foundations are five feet thick, a®deep as the nature of the ground required. TheF 1 ^or long sides, are supported by four counterforts, each si*.;broad, and four feet long, and their interval twelve ^between the intervals of the counterforts are air-holeorder to keep the magazine dry, and free from damp** esS ’ jer ydices of these air-holes are commonly a foot and a half e'^jway, and the vacant round them three inches, the insideoutsides being in the same direction. The dices serve to r g .vent an enemy from throwing fire in to burn the ma & a ^es®and, for a farther precaution, it is necessary to stop ^holes with several iron plates, that have small holes > B .j oflike a skimmer, otherwise fire might be tied to the o0 \isome small animal, and so drive it in that way; thisbe no hard matter to do, since, where this precautm