[No. 438]

The Silk Industry

The following brief note appeared in the official catalogue of the Indian and Colonial Exhibition, London, 1886: -
(Extracts from Reports, Colonial Sections, Colonial and Indian Exhibition, London, 1886.)

Species of cocoon and address of producer and exhibitor. - Mulberry-fed silkworm cocoon (Bombyx Mori).  Produced by Charles Anthony Brady, Tumbulgum, Tweed River, New South Wales, and exhibited by him in the New South Wales Court, Class 51, No. 332.
  Description of cocoon. 

Form Elliptical oblong, with slight medial depression.
Colour Creamy white inside and outside.
Texture Fairly compact.
Reeling Good.

Description of the bave of cocoons.  The reelable cocoon thread or bave is composed of two cylindrical fibres or brins, consisting of homogeneous matter (fibroi, Schorlemmer) surrounded and cemented together by a substance resembling gelatine (Sericin, or silk gelatin, Schorlemmer).  This latter is called "gum" in England and "gres" in France.  As with other mulberry silks, the two brins polarize light very beautifully when the bave is examined with the microscope, but the surrounding silk gelatine, which forms about 33 per cent of the total weight of the bave, has no polarizing power.  

Weight of cocoon 0.634 grammes
Dimensions of cocoon 32 x 16 millimetres
Length of bave reeled. 554 metres
Weight of bave reeled. 0.159 grammes
Fibre of bave in deniers 2.70
Mean diameter of bave 0.0328 millimetres
Mean elasticity of bave 18.1 per cent
Mean tenacity of strength of bave 6.7 grammes
Percentage of silk reeled from the cocoon 25.08 per cent.

Diameter, elasticity, and tenacity of the bave:-

  1. 10 metres from the end at the outside of the cocoon.
  2.      "                             "  at the middle of the cocoon.
  3.      "                             "  at the inside of the cocoon.


  (1) (2) (3)
Diameter of bave in ten-thousandths of a millimetre... 345 345 294
Percentage of elasticity, average of six estimates ... 16.7 22.8 14.9
Tenacity of breaking strength in grammes, average of six estimations ... 7.7 8.5 3.9

  Weight in milligrammes of each 100 metres of bave reeled from the cocoon, commencing at the end of the bave which is at the outside of the cocoon: -

(1) (2) (3) (4) (5) (6)
41 37 33 28 15 54

                               54 metres remained, weighting 5 milligrammes.
  The cocoons were ordinary buff-coloured, partially sun-dried, but not prepared otherwise.
  Mr Brady, in a printed circular, states that the climate on the Tweed River furnishes the mulberry-tree in great abundance, yielding daily supplies of the leaf from the end of July until April.  The soil, he says, is very fertile, the rainy season being from January to April, and followed by a dry winter.
    He states that he has, for many consecutive years, aided by the power of the climate and country, managed to obtain a continuous hatching of silkworms day by day or week by week, or, in his own words, "Assuming that the management of the eggs has been duly attended to at the proper time . . . . . the continuous hatchings will present 

NOTE: Metre = 39.37 inches.  1/10000 millimetre = 0.000003937 inch English.  100 inches of bave of quality indicated would stretch or extend before breaking to 118.1 inches.  1 gramme = 0.03527 ounce English.  The diameter and strength of the bave or natural pair of fibres are of course (?) double those of the single fibre or brin.
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