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Article A BRIEF SYSTEM OF CONCHOLOGY. ← Page 4 of 4
Note: This text has been automatically extracted via Optical Character Recognition (OCR) software.
A Brief System Of Conchology.
several of the c- linders , which have not the natural polish of the rest . Whe'i a shell is covered with a thick and fatty epidermis , as is the case with several of the muscles and iellinae ; in this case aquafortis wiii do n . ) service , as it will not tr > uch the skin : the ; : a tough brush and coarse emery are to be used ; and if this does not succeed , sealskin , or , as the workmen call it , fish-shin and pumice-stoneare to be
, employed . When a shell has a thick crust , which will not g ive way to any of these means , the only way left is to plunge it several irnes in o strong aquafortis , till the stubborn crust is wholly tiroded . The limpets , auris marina , the helmet-shells , and several other species of this kind , must have this sort of management ; but as the design is to
show the hidden beauties undet the crust , and not to destroy the natural beauty and polish of the in ide of the shell , the aquafortis must be used in this manner : A long piece of wax must be provided , and one end of it made perfectly to cover the whoL- mouth of the shell ; the other end will then serve as a handle , and the mou . h bein ;; - stop * ped by the waxthe liquor cannot get into the inside to spoil it ; then
, there must be placed on a table a vessel full of aquafortis , and another full of common water . The shell is to be plunged into the aquafortis ; and after remaining a few minutes in it , is to be taken out and plunged into the common water . The progress the aquafortis makes in eroding the surface is thus to be carefully observed every time it is . t . iken out : the point
of the shell , and any other tender parts , are to be covered with wax , to prevent the aquafortis from eating them away ; and if there be any worm-holes , they also must be stopped up with wax , otherwise the aquafortis would soon eat through in those places . When the repeated dippings into the aquafortis show that the coat is sufficientl y eaten away , then the shell is to be wrought carefully with fine emery and a brush ; and when it is polished as high as can be by this means
, it must be wiped clean , and rubbed over with gum water , or the white of an egg . In this sort of work the operator must always have the caution to wear gloves ; otherwise the least touch of the aquafortis will burn the fingers , and turn them yellow ; and often , if it be not regarded , will eat off the skin and the nails , These are the methods to be used with shells which require but a
moderate quantity of the surface to be taken off ; but there are others which require to have a larger quantity raken oh " , and to be uncovered deeper : this is called entirely scaling a shell . This is done by means of a horizontal wheel of lead or tin , impregnated with rough emery ; and the shell is wrought down in the same manner in which stones are wrought by the lapidary . Nothing is more difficulthowever
, , than the performing this work with jiicety ; very often shells are cut down too far by it , and wholly spoiled ; and to avoid this , a coarse vein must be often left standing in some place , and taken down after * wards with the file , when the cutting it down a , t the wheel would have spoiled the adjacent parts . Pro BE CONTINUED . ^
Note: This text has been automatically extracted via Optical Character Recognition (OCR) software.
A Brief System Of Conchology.
several of the c- linders , which have not the natural polish of the rest . Whe'i a shell is covered with a thick and fatty epidermis , as is the case with several of the muscles and iellinae ; in this case aquafortis wiii do n . ) service , as it will not tr > uch the skin : the ; : a tough brush and coarse emery are to be used ; and if this does not succeed , sealskin , or , as the workmen call it , fish-shin and pumice-stoneare to be
, employed . When a shell has a thick crust , which will not g ive way to any of these means , the only way left is to plunge it several irnes in o strong aquafortis , till the stubborn crust is wholly tiroded . The limpets , auris marina , the helmet-shells , and several other species of this kind , must have this sort of management ; but as the design is to
show the hidden beauties undet the crust , and not to destroy the natural beauty and polish of the in ide of the shell , the aquafortis must be used in this manner : A long piece of wax must be provided , and one end of it made perfectly to cover the whoL- mouth of the shell ; the other end will then serve as a handle , and the mou . h bein ;; - stop * ped by the waxthe liquor cannot get into the inside to spoil it ; then
, there must be placed on a table a vessel full of aquafortis , and another full of common water . The shell is to be plunged into the aquafortis ; and after remaining a few minutes in it , is to be taken out and plunged into the common water . The progress the aquafortis makes in eroding the surface is thus to be carefully observed every time it is . t . iken out : the point
of the shell , and any other tender parts , are to be covered with wax , to prevent the aquafortis from eating them away ; and if there be any worm-holes , they also must be stopped up with wax , otherwise the aquafortis would soon eat through in those places . When the repeated dippings into the aquafortis show that the coat is sufficientl y eaten away , then the shell is to be wrought carefully with fine emery and a brush ; and when it is polished as high as can be by this means
, it must be wiped clean , and rubbed over with gum water , or the white of an egg . In this sort of work the operator must always have the caution to wear gloves ; otherwise the least touch of the aquafortis will burn the fingers , and turn them yellow ; and often , if it be not regarded , will eat off the skin and the nails , These are the methods to be used with shells which require but a
moderate quantity of the surface to be taken off ; but there are others which require to have a larger quantity raken oh " , and to be uncovered deeper : this is called entirely scaling a shell . This is done by means of a horizontal wheel of lead or tin , impregnated with rough emery ; and the shell is wrought down in the same manner in which stones are wrought by the lapidary . Nothing is more difficulthowever
, , than the performing this work with jiicety ; very often shells are cut down too far by it , and wholly spoiled ; and to avoid this , a coarse vein must be often left standing in some place , and taken down after * wards with the file , when the cutting it down a , t the wheel would have spoiled the adjacent parts . Pro BE CONTINUED . ^