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Article TO SIR GEORGE STAUNTON, BART. ← Page 2 of 6 →
Note: This text has been automatically extracted via Optical Character Recognition (OCR) software.
To Sir George Staunton, Bart.
My intention , when I came to the iron works , was to raise an arch of at least two hundred feet span , but as it was late in the fall of last year , the season was too far advanced to work out of doors , and an arch of that extent too great to be worked within doors , and as I was unwilling to lose time , I moderated my ambition with a little common sense , and began with such an arch as could be compassed within some of the buildings belonging to the works . As the construction
of the American arch admits , in practice , of any species of curve with equal facility , I set off , in preference to all others , a catenarian arch of ninety feet span and five feet high . Were this arch converted into an arch of a circle , the diameter of its circle would be four hundred and ten feet . From the ordinates of the arch taken from the wall where the arch was struck , I produced a similar arch on the
floor whereon the work was to be fitted and framed , and there was something so apparently just when the work was set out , that the looking at it promised success . You will recollect that the model is composed of four parallel arched ribs , and as the number of ribs may be encreased at pleasure to any breadth an arch sufficient for a road-way may requireand
, the arches to any number the breadth of rivers may require , the constructing of one rib would determine for the whole ; because if one rib succeeded all the rest of the work to any extent is a repetition . In less time than I expected , and before the winter set in , 1 had fitted aud framed the arch , or properly the rib , completely together on
the floor ; it was then taken in pieces and stowed away during the winter , in a corner of a workshop , used in the mean time by the carpenters , where it occupied so small a compass as to be hid among the shavings , and though the extent of it is 90 feet , the depth of the arch at the center two feet nine inches , and the depth at the haunches six feet , the whole of it might , when in pieces , be put in an ordinarystage and sent to part of land
waggon any Eng . ' : I returned to the works in April and began to prepare for erecting ; we chose a situation , between a steel furnace and a workshop which served for butments . The distance between those buildings was about four feet more than the span of the arch , which we filled up with chunces of wood at each end . I mention this as I shall have ocr > casjon to refer to it hereafter .
We soon run upa center to turn the arch upon , and began our erection . Every part fitted to a mathematical exactness ; the raising ati arch of this construction is different to the method of raising a stone arch . In a stone arch they begin at the bottom or extremities of the arch , and work upwards meeting at the crown . In this we began at the crown by a line perpendicular thereto and worked downward each
vizy . It differs likewise in another respect . A stone arch is raised by sections of the curve , each stone being so , and this by concentric curves . The effect likewise of the arch upon the center is different ; for as stone arches sometimes breakdown the center by their weight , this , on the contrary , grew lig hter on the center as the arch increased " in thickness , so much so , that before the arch was completely finished
Note: This text has been automatically extracted via Optical Character Recognition (OCR) software.
To Sir George Staunton, Bart.
My intention , when I came to the iron works , was to raise an arch of at least two hundred feet span , but as it was late in the fall of last year , the season was too far advanced to work out of doors , and an arch of that extent too great to be worked within doors , and as I was unwilling to lose time , I moderated my ambition with a little common sense , and began with such an arch as could be compassed within some of the buildings belonging to the works . As the construction
of the American arch admits , in practice , of any species of curve with equal facility , I set off , in preference to all others , a catenarian arch of ninety feet span and five feet high . Were this arch converted into an arch of a circle , the diameter of its circle would be four hundred and ten feet . From the ordinates of the arch taken from the wall where the arch was struck , I produced a similar arch on the
floor whereon the work was to be fitted and framed , and there was something so apparently just when the work was set out , that the looking at it promised success . You will recollect that the model is composed of four parallel arched ribs , and as the number of ribs may be encreased at pleasure to any breadth an arch sufficient for a road-way may requireand
, the arches to any number the breadth of rivers may require , the constructing of one rib would determine for the whole ; because if one rib succeeded all the rest of the work to any extent is a repetition . In less time than I expected , and before the winter set in , 1 had fitted aud framed the arch , or properly the rib , completely together on
the floor ; it was then taken in pieces and stowed away during the winter , in a corner of a workshop , used in the mean time by the carpenters , where it occupied so small a compass as to be hid among the shavings , and though the extent of it is 90 feet , the depth of the arch at the center two feet nine inches , and the depth at the haunches six feet , the whole of it might , when in pieces , be put in an ordinarystage and sent to part of land
waggon any Eng . ' : I returned to the works in April and began to prepare for erecting ; we chose a situation , between a steel furnace and a workshop which served for butments . The distance between those buildings was about four feet more than the span of the arch , which we filled up with chunces of wood at each end . I mention this as I shall have ocr > casjon to refer to it hereafter .
We soon run upa center to turn the arch upon , and began our erection . Every part fitted to a mathematical exactness ; the raising ati arch of this construction is different to the method of raising a stone arch . In a stone arch they begin at the bottom or extremities of the arch , and work upwards meeting at the crown . In this we began at the crown by a line perpendicular thereto and worked downward each
vizy . It differs likewise in another respect . A stone arch is raised by sections of the curve , each stone being so , and this by concentric curves . The effect likewise of the arch upon the center is different ; for as stone arches sometimes breakdown the center by their weight , this , on the contrary , grew lig hter on the center as the arch increased " in thickness , so much so , that before the arch was completely finished