132 



NEW ENGLAND FARMER. 



From Rees'' Cydoptdia. 

 WOOL. 



[Continued from page 100.] 

 The weight of the fleece is an object offjreat 

 importance to the grower. It is generally sup- 

 posed by the English wool-dealers, that an in- 

 crease of weight implies an increase of coarse- 

 ness; indeed the words coarse and heavy are 

 considered by them as synonymous, but this is 

 not absolutely the case ; a fleece grown upon 

 the same animal may be increased in weight, 

 either by the fibres becoming coarser, or by 

 their being grown longer, or by a greater num- 

 ber of fibres being grown on the same skin. — 

 To the wool-grower it can never answer to in- 

 crease the weight of the fleece on small, fine- 

 wooled sheep, by growing the wool coarser; 

 if this be the object, the long-wooled breeds of 

 sheep are to be preferred. He may produce 

 wool somewhat longer by increasing the quan- 

 tity of food ; but it generally loses somewhat 

 of its fineness, and is less suitable for the clolh 

 trade. He may, however, increase the weight 

 considerably by selecting such breeds as grow 

 the wool close on the skin, and are thickly cov- 

 ered with wool over every part of the budy. — 

 Id this respect the Merino sheep have greatly 

 the advantage over any of the breeds of Eng- 

 lish sheep ; many of them yielding from three 

 to four pounds of pure wool, whilst the first 

 English fleeces rarely exceed two pounds, and 

 would lose one fourth of this weight when 

 brought to a pure state by scouring. It has been 

 doubted whether all sheep's wool, when clean, 

 possesses the same specific gravity ; but admit- 

 ting therft may be some variation in the wool 

 from different piles, we conceive that it is too 

 moderate to deserve the attention of the wool- 

 grower or manut'acturer. 



The filaments of fine wool beiug so minute, 

 it requires an eye habituated by long experi- 

 ence, to appreciate the relative fineness of two 

 piles, which may differ in value as much as 25; 

 percent. Even those who have been long! 

 practised in such examinafion find it difficult to 

 form, immediately, a correct opinion of the [ 

 fineness, if they are removed for a few weeks ' 

 from the opportunity of viewing wool. It is 

 not surprising then that the wool-grower, whoi 

 only directs his attention to the siibject during 

 one part of the year, should often be unable to 

 judge whether his wool has improved or not 

 since the preceding summer. On this account 

 it would be highly desirable that some easy and j 

 correct mode of admeasurement by the micro- 

 meter could be invented, which might enable 

 the observer to decide this with certainty. Mr 

 Daubenton employed a graduated scale, adapt- 

 ing it to the eye piece of a comijound micro- 

 scope ; but his method does not admit of accura- 

 cy. Mr Luccock made use of a more simple in- 

 strument, which we have seen ; it consisted of 

 R lens about half an inch in focal length, ad- 

 justed to a graduated scale. On this scale a 

 number of fibres were stretched and compress- 

 ed by a slider and screw into a given .space; 

 the filaments covering this space were then 

 coimted by the aid of the lens, ami a number of 

 admeasurements being taken of the same sort, 

 the mean of the whole was supposed to give 

 the correct diameter of the filament, in this 

 method, however, some of the filaments must 

 unavoidably overlap part of the others, on which 



account a greater number will be seen in a giv- 

 en space than there would be were the whole 

 diameter of each fibre visible. The error 

 from this may be stated at one-fifth. Thus Mr 

 Luccock makes the best English wool to mea- 

 sure the fourteen hundredth part of an inch, 

 which is finer than the best Spanish as measur- 

 ed by Dr Parry by a more accurate but more 

 laborious method. According to Mr Luccock, a 

 sample of moderately fine Spanish wool reach- 

 ed to the sixteen-hundredth part of an inch ; 

 according to Dr Parry, the very best Spanish 

 wool is not smaller than the fourteen-hundredth 

 part of an inch. 



With the above deduction of one fifih, which 

 we believe to be a near afipioximation to cor- 

 rectness, the diameter of the fibres of the best 

 English wool, as assorted in the usual method, 

 will Le nearly as follows: 



Paris of an Inch. 

 Prime - - - 1-1 120th 

 Choice - - - l-102-!ih 

 Sui)er - - - l-92Slh 



Head - - - 1-SOOth 



Downrights - - I-740lh 

 Seconds - - - l-610lh 

 Abb - - - l-530lh 



Fine livery (variable) l-4C0lh 



The method of measurement adopted by Mr 

 Luccock might be sufliciently correct with the 

 deduction of one-fit^th, were the instrument al- 

 ways used by the same |)erson,anda similar de- 

 gree of pressure given in each experiment; 

 but as this is required, it becomes uncertain in 

 its results, and inadequate to practical purposes. 



Dr Parry's method of measurement is effect- 

 ed by an instrument similar in principle to the 

 lam|) micrometer of Dr Herschel, of which an 

 account is published in the Pbilo.ropbiral 

 Transactions for 1732. An object of a known 

 diameter being placed in the focus of a com- 

 pound microscope, and strongly illuminated, 

 a piece of white paper is placed hor:zont:illy at 

 some distance beneath it ; then, looking through 

 the microscope with one eye, and keeping the 

 other steadily open, you will see the object ap- 

 parently projected on the paper, which is to be 

 measured while viewing it with a pair of com- 

 passes. Divide the length of the image so mea- 

 sured with the known diameter of the object, 

 which will give the magnifying power, the mi- 

 croscope. This being found, place the object 

 you wish to measure in the focu=, and project- 

 ing its imiige on the paper as before, measure 

 it with the compasses, and divi<le the results by 

 the magnifying power, which will be the real 

 magnitude of the object required. 



The light of a lamp is to be preferred to day 

 light, and the fibres to be measured are to be 

 stretched on a glass, and waxed down at both 

 ends. The under side of the glass should be 

 blackened with India ink, except in three parts, 

 the middle, and near the two ends. The un- 

 blackened spaces being placed in the focus of 

 the microscope, ten or more filaments may be 

 examined and measured successively, both in 

 the middle parts of the glass, and near the ends, 

 which will give the diameter of the filament at 

 the upper and lower end of the staple, and in 

 the middle. I'ach lock of ten filaments being 

 thus examined in three different parts, the ipean 

 of the three measurements must be taken for 

 the mean diameter of each lilament. and the 



mean diameter of the ten filaments may be tak- 

 en for the fineness of the whole lock. 



In (ilace of the blackened glass we would re- 

 commend a thin slide of ivory or brass, about 

 five inches in length, and half an inch in 

 breadth, with three transverse slits or openings 

 one in the middle, and the two others about 

 three lourths of an inch from each end. On 

 this slide the filaments fnay be stretched, it will 

 not be liable to break, aod the edges of the fil- 

 aments will be more correctly defined than 

 when a plate of glass is placed under them. 



The farther the paper is removed from the 

 eye, the larger will be the apparent space cov- 

 ered by the image of the object, but it must 

 ! not he too far for the hand to measure it with 

 j compasses. But if in place of the compasses 

 we hive a paate-board graduated into minute 

 divisiins tVom a black line upwards, and a slid- 

 ing index be adjusted, the paste-board may be 

 placed at a much greater distance, the observ- 

 er adjusting the slide, u",til the edge of it and 

 the black line coincide with both edges of the 

 filament. A horizontal position for tbe micro- 

 scope will be most convenient, illuminating tlie 

 object with a lamp and lens. In this way the 

 appar-^nt duimeler may be greatly increased, 

 and we. think the observations might be made 

 with irrealer ease and accuracy. 



Ey the above method the diameter of very 

 tnihule filaments may be ascertained, and mi- 

 nute ilifTerences detected, which the unassisted 

 eye is unable to detect. We are aware, how- 

 ever, that it requires some address and time 

 10 enable the observer to manage the instru- 

 ment, on which account it cannot, we fear, be 

 made generally useful. 



[^To be continued.^ 



From the Farmer's Assistant. 



ON BEES. 



What has lately proved most destrucfive to 

 Bees, in this Country, is an insect, w hich is the 

 spurious tinea, while in its cateipillar form. It 

 is a species of moth, and is thus described by jlf. 

 Raimnur . 



'• These creatures are of (he caterpillar kind, 

 and have sixteen legs. They feed on wax, and 

 for food enter the beeliives; where they boldly 

 engage tbe Bees, and ate not to be prevented 

 by them from feeding, though at the expense of 

 their habitations ; so that it is no uncommon 

 thing for a swarm of Bees to be forced to change 

 their place, leaving this contemptible victor io 

 possession of the hive.' 



" All the Authors who have writen on Bees, 

 have complained of this destructive animal. It 

 never eats the honey, but feeds only on Ihe 

 was; attacking principally those waxy cells 

 where the female Bee deposits her eggs for the 

 future progeny.' 



"The Bees would readily destroy these creat- 

 ures, were it not tor the armor they are covered 

 with. They form themselves a coat of armor 

 of a double mailer. The first, next to the body, 

 is a kind of silk of their own spinning; and the 

 outer covering is of beeswax, laid on considera- 

 bly thick. The creature, just thrusting its head 

 out to feed, goes on devouring the cells ; while 

 the Bees are buzzing about him, attempting ia 

 vain to pierce him with their stings. He never 

 forsakes his covering ; but lengthens and enlar- 

 ges it as he goes; and, gnawing down the sides 



