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Article A BRIEF SYSTEM OF CONCHOLOGY. Page 1 of 4 →
Note: This text has been automatically extracted via Optical Character Recognition (OCR) software.
A Brief System Of Conchology.
A BRIEF SYSTEM OF CONCHOLOGY .
^ CONCLUDED FROM OUR LAST . ^
A FTER the shell is thus cut down to a proper degree , it is to be po-- * ¦*• fished with fine eir . erv , tripoli , or rotten-stone . with a wooden wheel turned by the same machine as the leaden one , or by the common method of working with the hand with the same ingredients . When a shell is full of tubercles , or protuberances , which must be preserved , it is then impossible to use the wheel : and if the common way of dipping into aquafortis be attemptedthe tubercles being harder than
, the rest of the shell , will be eat through before the rest is sufficiently scaled , and the shell will be spoiled . In this case , industry and patience are the onty mqans of effecting a polish . A camel ' s hair pencil must be dipped in aquafortis ; and with this the intermediate parts of the shell must be wetted , leaving the protuberances dry : this is to be often repeated ; and after a few moments the shell is
alwa 3 's to be plunged into water , to stop the erosion of the acid , which would otherwise eat too deep , and destnty the beauty of the shell . When this has sufficiently taken off the foulness of ' the shell , it is to be polished with emery of the finest kind , or with tripoli , by means of a small stick , or the common polishing-stone used by the goldsmiths mav be used .
This is a very tedious and troublesome thing , especially when the echinated oysters and murices , and other such shells , are to be wrought : and what is worst of all is , that when all this labour has been employed , the business is not well done ; for there still remain several places which could not be reached by any instrument , so that the shell must necessaril y be rubbed over with gum-water or the white of an egg afterwards , in order to bring out the colours and give a gloss ; in some cases it is even necessary to give a coat of varnish .
These are the means used by artists to brighten the colours and add to the beauty - of shells ; and the changes produced by polishing in this manner are so great , that the shell can scarcely be known afterwards to be the same it was ; and hence we hear of new shells in the cabinets of collectors which have no real existence as separate species , but are shells well known , disguised by polishing . To caution the reade , r against errors of this kind , it may be proper to add the
most remarkable species thus usually altered . , The onyx shell or volute , called by us the purple or violet-tip , which , in its natural state , is of a simple pale brown , when it is wrought sli g htly , or polished with just the superficies taken off , is of a fine bright yellow ; and when'it is eaten away deeper , it appears of a line milk-white , with the lower part blueish : it is in this state that it is called the cny . r-sbel !; and it is preserved in many cabinets in its
Note: This text has been automatically extracted via Optical Character Recognition (OCR) software.
A Brief System Of Conchology.
A BRIEF SYSTEM OF CONCHOLOGY .
^ CONCLUDED FROM OUR LAST . ^
A FTER the shell is thus cut down to a proper degree , it is to be po-- * ¦*• fished with fine eir . erv , tripoli , or rotten-stone . with a wooden wheel turned by the same machine as the leaden one , or by the common method of working with the hand with the same ingredients . When a shell is full of tubercles , or protuberances , which must be preserved , it is then impossible to use the wheel : and if the common way of dipping into aquafortis be attemptedthe tubercles being harder than
, the rest of the shell , will be eat through before the rest is sufficiently scaled , and the shell will be spoiled . In this case , industry and patience are the onty mqans of effecting a polish . A camel ' s hair pencil must be dipped in aquafortis ; and with this the intermediate parts of the shell must be wetted , leaving the protuberances dry : this is to be often repeated ; and after a few moments the shell is
alwa 3 's to be plunged into water , to stop the erosion of the acid , which would otherwise eat too deep , and destnty the beauty of the shell . When this has sufficiently taken off the foulness of ' the shell , it is to be polished with emery of the finest kind , or with tripoli , by means of a small stick , or the common polishing-stone used by the goldsmiths mav be used .
This is a very tedious and troublesome thing , especially when the echinated oysters and murices , and other such shells , are to be wrought : and what is worst of all is , that when all this labour has been employed , the business is not well done ; for there still remain several places which could not be reached by any instrument , so that the shell must necessaril y be rubbed over with gum-water or the white of an egg afterwards , in order to bring out the colours and give a gloss ; in some cases it is even necessary to give a coat of varnish .
These are the means used by artists to brighten the colours and add to the beauty - of shells ; and the changes produced by polishing in this manner are so great , that the shell can scarcely be known afterwards to be the same it was ; and hence we hear of new shells in the cabinets of collectors which have no real existence as separate species , but are shells well known , disguised by polishing . To caution the reade , r against errors of this kind , it may be proper to add the
most remarkable species thus usually altered . , The onyx shell or volute , called by us the purple or violet-tip , which , in its natural state , is of a simple pale brown , when it is wrought sli g htly , or polished with just the superficies taken off , is of a fine bright yellow ; and when'it is eaten away deeper , it appears of a line milk-white , with the lower part blueish : it is in this state that it is called the cny . r-sbel !; and it is preserved in many cabinets in its