PEARL ESSENCE 17 



Bourguignon in France, and the term honrguignon came to be used 

 to denote imitation pearls. By the time of the American Revolution 

 a factory at St. Jean de Maizel was producing 10,000 pearls a day. 



The first extensive account of the use of essence d'Orient (the French 

 term for pearl essence) was that of Reaumur (1716), already referred 

 to. This ^vriter seems to have been the first to discover, or at least 

 to record, that the essence is not a homogeneous liquid but a suspen- 

 sion of a vast number of minute particles shaped like blades. 

 Reaumur evidently did much work on the subject. He describes at 

 length the distribution of the lustrous substance among the tissues of 

 fishes — peritoneum, stomach, scales, iris, etc. — and constructs an 

 elaborate though wholly erroneous theory to explain how it may be 

 produced in the stomach and intestines and transported through 

 minute canals to the surface, where it is distributed and deposited in 

 the scales. He also describes the process of making the essence and 

 applying it to beads. The scales of the ablette were agitated with 

 water in a bowl, the water being poured off and renewed, again agi- 

 tated, and so on until the scales were clean. The wash waters were 

 mixed, the suspended particles allowed to settle for 10 to 12 hours, 

 and the clear excess of water was decanted. The concentrated sus- 

 pension left was essence d'Orient. No mention is made of the use of 

 ammonia. The essence was quite unstable, especially in warm 

 weather, when it decomposed and lost its luster. He says that during 

 a storm it will decompose from one hour to the next. 



The essence was applied by means of fish glue to beads of wax, ala- 

 baster, or glass. Since these were sensitive to moisture, the next 

 improvement was to blow hollow spheres of glass — blue, greenish, or 

 ''gyrasole'' (opal) — and coat them inside with the fish glue and pearl 

 essence mixture. 



Referring to the beautiful but indescribable whirling effects seen 

 in the liquid pearl essence, Reaumur says of the tiny blades : 



They yield so easily to such slight movements that I do not doubt that they 

 have been taken for insects by those who are disposed to give that name to every- 

 thing which moves continually in liquids. 



If we judge from the numerous references in the literature about 

 Reaumur's time we will readily conclude that pearls were very much 

 in fashion, and that there was a lively interest in the nature of pearls 

 and the possibility of producing them artificially. It was only a few 

 years later that the great Swedish botanist, Linnaeus, announced the 

 discovery of an artificial method of inducing pearl formation in mol- 

 lusks. The method remained a secret and was lost. 



Beckmann (1786) described the process of making the essence very 

 much as Reaumur did, only by this time it had been discovered that 

 "volatile alcali" (ammonia) helps to dissolve the epidermal tissue and 

 also preserves the essence. He described also the introduction of the 

 mixture into the beads with a fine pipette, and how the beads were 

 kept in motion on a swinging cradle to obtain uniform distribution of 

 the coating. After the coating was dry, the bulb was filled with wax 

 and strung. Colors were used. Small paper tubes were inserted 

 through the better grades to prevent the thread from becoming waxed. 



HISTORY OF CHEMICAL RESEARCH OX PEARL ESSENCE 



The next paper of importance was by Ehrenberg (1833), on the 

 formation of crystals in the tissues of living animals. In this paper 



