July 2, 1883.] 



THE TROPICAL AGRICULTURIST. 



71 



reared under rather disadvantageous circumstances as re- 

 gards weatlier. The hatching of the eggs of the silkworm 

 takes place about the 20th April, and according to Chinese 

 accounts the rearing should be accomplished, if the 

 weather is warm, say 69' to 74°, in 23 to 24 days. 

 The books read thus: 



"If the meals of mulberry leaves be given frequently 

 the warms will advance rapidly to maturity; and if sel- 

 dom they will be long in arri%'ing at the mature age. If 

 this stage be arrived at iu 25 days it is calculated that 

 each hurdle of worms will produce 25 ounces ; of silk ; if 

 in 28 days then each hurdle will produce ouly 20 ounces; 

 but if the worms are a month or 40 days in coming to 

 maturity then each hurdle will only give ten or a dozen 

 oimces; when the silkworms tall into and awake from 

 their torpor at irregular intervals the silk will be defici- 

 ent in quantity. After the great (fourth) torpor, silkworms 

 only require fifteen or sixteen meals before they arrive 

 at maturity." And these meals must be very large ones, 

 as may be judged from the following remark : " When 

 the worms are aroused from their third torpor, put a 

 pound of them in one basket, from which you will after- 

 wards obtain eight pounds' weight of cocoons." 



The silkworm as a rule objects to damp moist weather, 

 changes of temperature, and clouds charged with electricity ; 

 when these occur in the fifth age, or after the fourth sleep 

 or torpor, the mortality becomes very great, the worms are 

 attacked with a faclierie, or wasting away, they refuse to eat 

 and die. It is ouly necessary to refer to the meteorological 

 tables pubUshed from the Siccawei Observatory to discover 

 what would most probably be the weather in the Bilk-<Ustricts 

 at the critical ages of the silkworm ; and as they live Ti 

 days before arriving at the fifth age, it follows that on the 

 13th ilay,-th8 worms hatched on the 20th April would be in 

 their critical period and the vicissitudes of the weather 

 would have their worst effects. On a reference to the 

 weathi-r tables of the 12th to 15tli May, we find ihat the 

 weather was exceedingly wet aud boisterous, and that 

 thunderstorms and damp mists and muggy weather were the 

 rule. Father Marc Dechevrens explamed that it was caused 

 by thedobrisof a typhoon, and referred to the weather of 

 the past month as deplorable. Father Dechevrens also says 

 that since the vernal equinox no fewer than thirty \vhirl- 

 wind have been observed at Siccawei. That considerable 

 damage has been done can be iufened from the Chinese 

 statements, which have the probahihty, or rather the cert- 

 ainty, of being correct, aud if any further testimony be 

 needed it may be found iu the low price of mulberry le ives, 

 which tends to show that in their most voracious age there 

 are not worms enough to consume the supply of leaves. — 

 Xortit China Herald. 



COKK.« 



Cork is yielded by the cork oak, Quercvs liber, which 

 chiefly flourishes on the shores of the Mediterranean. There 

 are, in Spain and Algeria, large forests of this tree, which 

 is also cultivated in the dej)artments of Lot-et-Garoune, 

 and Var, iu the south of France, and in Corsica. 



The cork oak arrives at its full growth in about 100 

 years, when, iu hot climates, it attains a height of sixty or 

 seventy feet, with a diameter of six to eight feet. The bark 

 consists of two distinct portions, the inner formed of a 

 fibrous tissue, and the outer, tuberous, and of a porous and 

 elastic consistency, which constitutes the cork proper. The 

 first cork uaturaily produced by the tree is called the male, 

 and has scarcely any value ; but if this be removed, a second 

 layer is formed, finer, more elastic, and less irregular, which 

 is knoTCu as the female -cork ; and this it is which is 

 generally used. 



The stripping or the cork takes place in summer, when 

 the circulation of the sap facilitates the separation of the 

 outer from the inner layer of bark. The removal of the 

 first growth is affected when the tree is twenty to twenty- 

 five years old. Several annular incisions, and one vertical 

 incision, arti made with a hatchet, care being taken to cut 

 the cork ouly, without touching the inner bark ; the layer 



• Abstracted from a paper by M. Henry Mamy, Ingenieur 

 des Arts et Manufactures, iu the columns of the Monitmr 

 /iidustrid. 



of cork is then easily detached. A young oak yields about 

 10 lb. of cork at the first stripping, while it "is capable, 

 ultimately, of yielding, over 3O0 lb. The first cork has a' 

 thick and hard exterior, which diminishes with each suc- 

 cessive growth. Formerly, after the first stripping, the tree 

 was left to itself without any protection. Being very tender 

 it was hable ""o be killed by exposure to variations of temperat- 

 ure, while numerous insects attacking the tender surface 

 of the tree, reduced the value of the future cork. Besides 

 a thick and irregular crust formed, which it was necessary 

 to remove, thus causing a loss of 30 per cent of cork. 



A better plan ie to employ the method of M. Capgrand- 

 Mothes, which consists in covering the tree during several 

 months after stri jping, with the cork which has been removed. 

 A few vertical incisions are made in the inner bark, to pre- 

 vent irregular furrows being formed. The pieces of bark are 

 then restored, being fastened by iron wire ; and the joints 

 are made good underneath with strips of cellulose card- 

 board. After three months, in the autumn, the pieces of 

 bark have become quite dry, and are taken ofi'. The effect 

 of this practice is to induce the formation of a protecting 

 layer, tuberous, homogeneous, and elastic, under which tbe 

 growth of the cork goes on without danger of injury. 



The detached pieces of cork, flattened by being piled 

 up with the outside uppermost, are freed from their ex- 

 ternal surface by boiling an4l paring. The boiling of the 

 cork, which lasts about haif-an-hour, is effected in large 

 cubical boilers fired with refuse cork, and closed by a cover 

 which presses upon the pieces. The paring is done bv 

 hand, or by means of horizontal rollers provided with iron 

 blades ; but this last-named operation may be dispensed with 

 when the practice of covering the tree with the detached 

 pieces of hark is adopted. 



The principal use of the outer bark is to make bottle corks 

 They are more frequently cut by hand, though sometimes by 

 a machine, a horizontal knife giving a rotary motion to 

 the piece of cork, aud thus cutting it into a cylindrical 

 form. Cork is also used for making life-buoys, swimming- 

 belts, floats, non-conducting linings, &e. It is moreover 

 used advantageously in the form of powder, for packing 

 fragile objects, as a substitute for lycopoilium powder and 

 for the manufacture of linoleum and cork-leather. Cork 

 is, however, on account of its el.asticity, reduced to powder 

 with great difficulty. To effect this, mills with grinders in 

 the shape of rasps, mill-stones revohing iu a pan, and arti- 

 ficial stones revolving at great speed, are employed. 



Linoleum consists of cork-powder consolidated with dried 

 linseed oil. The mixture, in the proportion of about 3 

 parts of oil to I of cork-powder, is passed under heavy 

 rollers, and then stuck on to cloth by means of drying oil. 

 It is allowed to dry for about three months, when the pro- 

 duct is ready to receive various designs, and may be readily 

 washed. Linoleum is adulterated by adding sawilust tj the 

 cork-powder. Cork-leather, which is waterproof and very 

 elastic, is cork-powder consolidated with iudiaruhber. 



Cork refuse is used for making partitions that do not 

 conduct heat or souud ; it also yields a light and porous 

 charccal. M. Combe d' Alma has proposed to distil them, 

 so as to obtain a very rich gas, free from sulphuretted' 

 hydrogen. Old bottle corks are sometimes collected, boiled 

 and washed in acidulated water for again serving to cork 

 bolttes. — Journal of the Society of Arts. 



THE VALUE OF TEA. 

 [There is much useful information and souud good 

 sense embodied in this paper by our good friend Mr 

 Moody, the leading tea e.vpert in Australian colonies. 

 The only deGciency is that of a reference to theun. 

 doultHd nutriment in tea. We would also say em- 

 phatically tbut, while boiled tea is beastly, the best 

 tea will fail to give out its virtues if the water 

 poured on it iu the heated teapot is not perfectly 

 boiling ; while if the best-and-best made tea is allowed 

 to be much over ten minutes iu tho pot it is ruined 

 —Ed. T. a. 



Br J. 0. Moody. (From the Border Watch.) 

 The Australian Colonies consume about 18,000,000 pouud 



