Amongst other hints to the collector of old Oriental porcelain must be one with regard to cracked and mended porcelain. By this we mean not alone those pieces which are built up as far as some particular part is concerned, and which can be tested by striking the various parts with a coin, when the difference between the ring of the original part and the dull sound from the composition used in mending may be easily detected. Further, the sense of smell may be brought into play. Generally, the composition used in mending old porcelain in this way smells of oil or turpentine. The third test may be applied by means of a magnifying-glass which will at once reveal the difference between the smooth original glaze and the varnish glaze added to cover the mend. But this is not all. Some mending is done at the factories, where a piece of porcelain of the same tone and colour, with the same decoration, is built and fixed on to the sound piece in such a way as to leave no trace that can be detected by sound, sight, or smell. In this case it really matters very little, as the character of the old porcelain is so well preserved that the piece may be regarded as being perfect. A very simple test for detecting a repair in porcelain is to pass the point of a pin, not too heavily, over the suspected part, when if the original has been at all interfered with, scratches and marks of the pin will be easily seen.
Nearly the whole of Oriental porcelain is hard paste. By this we mean it cannot be cut with a file. Both paste and glaze are hard, and although some people speak of soft-paste Oriental porcelain our observation teaches us that it is so rare that it may be neglected by the ordinary collector, who, if he should accidentally find a piece, will remember that this soft paste is of a very white colour with an opaque look, and for painting under the glaze seemed to have the disadvantage that the colours were more liable to run than on the ordinary description, which is just like what has been found on early English soft-paste porcelain, where the colours are liable to run upon the paste. In the Chinese soft paste better effect was produced by the hatching and stippling style of decoration which was adopted in later times and superseded the broad washes adopted in the Kang-he period.