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nerally found, that a blue flough covers the whole of the 

 eye, without any intermixture of red vefTels. That in the 

 worft cafes, the coloured and tranfparent part of the eve 

 becomes of a reddifh-white ; by wliich time, the film on the 

 eye has acquired confiderable thicknefs and hardnefs. That 

 the inflammation is produced in various ways, and by'various 

 means; as during the fummer feafon by the reflexion of 

 heat and light in very funny and dry weather, as it is found 

 to be more frequent when the hilly fheep-walks become 

 fcorched, and on hard rocky foils, than on the dark-coloured 

 hills which are covered with heather. Others fuppofe, that 

 the difeafe is fometimes caufed by the pollen or duft of 

 flowers irritating the eyes of the (heep, when blown into 

 them, in confiderable quantities, by the wind. That in the 

 winter, the blindnefs is caufed and occurs when the days are 

 very funny, and the evenings frofty and cold ; or when the 

 flieep have been long buried under fnow, and the ground is 



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Davy's " Elements of Chemical Philofophy," that the 

 combination of barytes and carbonic acid, made artificially 

 by pouring a folution of carbonate of ammonia into a folu- 

 tion of nitrate of barytes, forms alfo a pigment of a very 

 white colour. 



White Colours, in Dyeing. See Colour. 



White Copper Ore, in Mineralogy, is one of the rareft 

 ores of copper, and has frequently been confounded with 

 copper pyrites, and other ores of that metal. ( See Copper 

 Ores.) Its colour is between filver-white and bronze- 

 yellow ; it occurs maffive and difleminated ; it has a metal- 

 lic luftre. The fraiSlure is fine-grained and uneven ; it yields 

 eafily to the knife. The fpecific gravity of this ore is 4.5. 

 It contains about 40 per cent, of copper mixed with iron, 

 arfenic, and fulphur. 



White Copperas, Cordage, Eagle, and Egg-Shell. See 

 the fubftantives. 



White CoJs -Lettuce for Hogs, in Agriculture, the ufe of ftill white and glaring when they get out. 

 it in feeding thefe animals. A trial of it in this way is ftated But by ftill others, the blindnefs in flieep is believed to 

 to have been made in Suffex, which is particularly deferving arife from a caufe wholly different from any of thefe. That 

 of attention : the weaning of young pigs, without much it is induced by a continued fatigue for a length of time 



■ milk and fome corn, is often a difficult bufinefs ; but if this which is capable of bringing it on at any feafon of the year! 



■ fort of lettuce will do it, which feems to be the cafe, no Thus, ftieep that are long and hard driven, or fuch as are 

 ; farmer ftiould ever be without a rood, or half an acre of this 

 t fort of crop for this ufe. 



In this trial, four ounces of this fort of lettuce-feed were 

 ' fown very thick over two perches of ground in the beginning 

 of March. A crop of potatoes was in rows at three feet 

 diftance ; between which a double row of thefe lettuces was 

 planted in May ; both crops being afterwards kept clean by 

 hand-hoeing. In the June following, they were begun to be 

 ufed for three fows with little pigs, which were kept on 

 thefe lettuces for fix weeks; but thefe fows hadwafh in ad- 

 dition : the pigs were then weaned a fortnight earlier than 

 ufual ; and after the weaning, the great ufe of the lettuces 

 was found, for the pigs did admirably well upon them, 

 until they all were gone in the middle of Auguft. They 

 were then fed as ufual, with cabbage, turnip-tops, and other 



daily dragged from one part of the ground to another, ewes 

 that ^re did, or old, and roughly handled and ufed by tlie 

 vyomen in milking, during the operation, where that prac- 

 tice is in ufe, and hog-flieep which are tired by driving 

 through fnow, in order to preferve their fubfifl;ence, are all 

 liable to this affeftion of the eyes. That their eyes at firft 

 become fore, and emit a fort of ropy humour ; after which 

 a white film fettles over them, and if they continue to be 

 fatigued, it grows thicker, the eyes appeanng perfeftly 

 white ; in which cafes, they are faid to be proportionably 

 longer in getting better. The difeafe, too, may proceed 

 from many other caufes of diff'erent kinds, as all fuch as 

 tend to caufe local inflammation in the parts, as cold, moif- 

 ture, and many others of the fame fort. 

 . . In the cure of the difeafe, where it is fufpefted to arife 



fuch vegetable matters, but fell off at once for want of the from the irritating powdery matter of flowers, the flieep 



lettuces. See Lactuca, and Lettuce. '' — u l- ^ — i- . 1 , , „ . 



White Crops, a term applied to all forts of grain-crops, 



as wheat, rye, barley, oats, and fome others, in contra- 



diftinftion to thofe of the green and culmiferous kinds, fuch 



as cabbages, turnips, rape, tares, beans, and fome others 



of a fimilar nature. 



White Darnel, a very troublefome and prolific weed 



among corn-crops, efpecially of the wheat kind. See 



Weed, &c. 



White Enamel. See Enamel, and Enamelling. 

 White Face, or Blaze, in the Manege, a white mark 



upon a horfe, defcending from the forehead almoil to the 



nofe. It is called in French chanfrin blanc. 



fliould be immediately removed to other proper paftures for 

 a time, until the danger from that caufe is over ; and in 

 cafes of fnow-blindnefs of this kind, it is always proper 

 to bring them down, as foon as poffible, from the high 

 fnowy walks, where they occupy them, to the bare grounds 

 below. 



The inflamed veflTels on the white of the eye, efpecially 

 thofe next the nofe, are alfo fometimes advifed to be cut with 

 a lancet or fliarp penknife every fecond morning ; while the 

 eyes are to be kept defended againft the light, by a fliade 

 tied over the head, or a piece of crape over the eyes. The 

 eyes may likewife be bathed two or three times a-day, with 

 a folution of half a drachm of fugar of lead, or of two 

 White Film, or Blindnefs, a difeafe in flieep, which is oc- drachms of alum, and the fame quantity of white vitriol, in 



cafioned by a white film growing over their eyes, in confe- 

 quence of fome fort of inflammation, as arifing from dif- 

 ferent caufes, taking place in them. 



The appearances by which it is fliewn to be prefent are, 

 according to fome, that the animal cannot bear the light, 

 that the white part of the eye is red and inflamed, and that 

 it waters a great deal. That this ftate is fucceeded by a fort 

 of membrane or coat formed by the inflamed veffels, which 

 firft covers the white, but gradually extends over the eye, 

 until total blindnefs is the confequence. That this is noticed 

 to be the cafe, when in folding, the ftieep run againft dykes, 

 or any other fuch obftacles, and ftart when they approach 

 them ; that they do not follow the flock, and that they fre- 

 quently ftumble. That when the eye is infpefted, it is ge- 



a pint of foft -water. At the fame time purgatives may be 

 given internally, fuch as two ounces of fome purging falts, 

 or, what is better, a fcruple of calomel, once a day for four 

 or five times. When, by thefe means, the inflammation is 

 got the better of, but the flough ftill remains, a little oint- 

 ment, compofed of eight parts of fome mild unftuous fub- 

 ftance, and one of red precipitate of mercury, made fine 

 by rubbing, may be infinuated into the eyes every morning; 

 or a little finely powdered cryftal and loaf fugar be blown 

 into them twice in the day. 



With fome, it is at firft the praftice to bleed the flieep 

 below the eyes, and to let fome of the blood run into each 

 of them ; but it is fuppofed that care will infallibly cure the 

 difeafe m a (pace of time proportioned to the debility that 



has 



