Written for the Scientific American By Dr. M.Reimann, of Berlin Supposing it is required to dye 100 lbs. of raw silk, 12 lbs. of soap are boiled with a sufficient quantity of river or rain water until all the soap is dissolved ; the water is then allowed to cool a little and the silk is introduced ; it is allowed to remain in the solution of soap 1 hours, the liquid in the meantime being kept at the boiling temperature. The silk is then wrung dry, put into linen bags, and once more introduced into a solution of 12 lbs. of soap. It is once more boiled for 1-J hours, and finally washed in the river. PBEPABATION OF SECOND-HAND SILK STUM'S.—The silk is cleaned in a warm solution of carbonate of soda, then boiled lor an hour and a half in a soap bath, and washed in the river. It is next placed in water acidulated with a little sulphuric acid, and suffered to remain in it until the original color has wholly disappeared. It is then washed finally in the river. To DYE SILK BLUB.—The silk is immersed for some time in a solution of alum, whichserves as the mordant. Meantime a solution of indigo carmine in boiling water is mixed with warm water in a suitable vessel. In order to dye 10 lbs. of silk f lb. of indigo is requisite. The silk is immersed in this bath until the requisite shade is obtained. It is then wrung out and allowed to dry in the shade. In order to give a deeper tint to the material, the silk is passed through an indigo vat. In this way the deepest tints may be obtained. To DTE SILK GBEENISHBLUE.—In order to dye 10 lbs. of silk, 1 lb. of alum is dissolved in a sufficient quantity of water to completely cover the silk ; ? oz. of sulphuric acid is then added, and the silk is allowed to remain. 4 hours in the bath. It is then taken out and wrung dry. A solution of or f lb. of indigo carmine in warm water is then added to the alum bath, well mixed by stirring, and the silk once more introduced. It is suffered to remain in the dyeing bath until a sufficiently dark shade has been obtained. It is then taken out, wrung out, dried, and completed. In order to obtain a uniform color the indigo is gradually introduced into the bath. A EBDDISH-BLUB DTE.—In order to dye 10 lbs. of silk J lb. of protochloride of tin is dissolved in water, and to this solution are added 2 lbs. of solution of nitrate of iron and 1 oz. of sulphuric acid. The mixture is allowed to stand a day and the clear portion of the liquid is then poured into a sufficient quantity of water. The silk is submitted to the action of the mordant thus obtained for half an hour. It is then wrung out, washed in river water, and finally dyed in a bath containing lb. of yellow prussiate of potash and lb. of sulphuric acid. The dyeing operation should continue a quarter of an hour. The silk is wrung out, introduced once more into the mordant bath, then dyed as before, and so on until the shade obtained is dark enough. When this is the case the silk is washed, dried, and finished. YELLOW DYE BY MEANS OF WELD.—In order to dye 10 lbs. of silk, 3 or 4 lbs. of weld are boiled in water for 20 minutes; the decoction is then filtered through linen and suffered to cool a little. The silk is then boiled as before with one fifth of its weight of soap, then allowed to remain some time in an alum bath, and finally introduced into the above-mentioned weld decoction. Here it is worked about until it is uniformly dyed. A little carbonate of potash may be added to the weld bath in order to vary the shade a little. The yellow tint obtained from weld is sufficiently deep. YELLOW DYE BY MEANS OF QUEKCITEON.—In order to dye 10 lbs. of silk, 5 lbs. of quercitron bark are boiled with a sufficient quantity of water ; the clear decoction is then poured off, and the silk previously mordanted by alum is immersed in it for half an hour and then washed. By varying the amount of quercitron and adding crystals of soda, various shades of yellow may be obtained. It is a good plan to add some gelatine to the decoction of quercitron before making use of it, as in this way the tannic acid contained in the quercitron bark may be removed from the liquid, BBIMSTONM COLOS st MIASS of Vxc&m Aem—Picric Mid k tery tfts ewpteyed st tfcs psesest dy te giv ft light f$U low tint to silk. With regard to the nature of picric acid, it is one of the products obtained from coal tar. Among the products obtained by the distillation of coal tar at a temperature varying from 150 to 190 Centigrade, is an oil which contains a considerable quantity of carbolic acid. The benzole being the hydride of phenyl Cn H6 H, phenyl the carbolic acid is the alcohol C12 H5 O -j- HO, but is phenyl indued with acid properties. On treating the oil containing carbolic or phenic acid with solution of soda, decanting the clear solution of phenylate of soda and adding sulphuric acid to it, an oil is obtained which when distilled and dried, furnishes crystals of pure phenic acid. This substance, when heated with nitric acid, readily furnishes products in which hydrogen is replaced by the complex atom NO+ or subnitric acid. On heating phenic acid with three equivalents of nitric acid, a product is obtained in which three equivalents of N04 have taken the place of three equivalents of H, thus C H5 O + HO + 3NO5=Cl;; H2 O + HO + SHO (NO*)3 The whole mass has the appearance of a yellow crystalline paste, which, on being dissolved in boiling water and recrys-tallized, furnishes yellow crystals to which chemists have applied the name "trinitrophenic acid." In commerce it is called "picric acid," " Welter's bitter," and " picronitric acid." In a state of purity it is a yellow crystalline substance, having a Very bitter taste, and soluble in cold water, which has a brimstone yellow tint when holding this substance in solution. All animal substances when dipped in this solution of picric acid are dyed yellow. Therefore, the the silk has only to be introduced into a solution of the acid containing for every 10 lbs. of silk to be dyed 2 ozs. of picric acid, when a fine brimstone shade will be readily obtained. The color easily resists the action of sunlight and of air but readily disappears on washing with soap or even with clean water. Therefore the silk must never be washed after dyeing, but merely dyed in the solution and then finished. The yellow color produced by picric acid may be easily discovered by applying the tongue to the dyed article. The exceedingly bitter taste is a satisfactory proof that picric acid is deposited on the fibers. YELLOW DYE PBODUCED BY ANNOTTO.—In order to dye 10 lbs. of silk, lb. of annotto is boiled for half an hour with a solution of lb. of carbonate of potash and a sufficient quantity of water. The silk is introduced into this bath and well worked about, while the temperature of the bath is kept close upon the boiling point, though never actually boiling. The requisite shade having been obtained, the silk is washed, then heated at 40 or 50 Centigrade with alum, in the solution of which it is allowed to remain a night. In the morning it is again washed and dyed a second time in a bath at a temperature of 30 Centigrade, which contains a decoction of weld and a quantity of the soap used before for the purpose of cleaning the silk. The dyeing operation is effected by passing the silk seven times through the bath. The above-mentioned weld decoction is prepared by boiling 20 lbs. of weld with 10 gallons of water and lb. of carbonate of potash. The silk, when sufficiently dyed, is passed through a soap bath containing 3 lbs. of white soap. AN OBANGE DYE.—In order to impart an orange tint to 10 lbs. of silk, 1 lb. of annotto and 3 lbs. of carbonate of soda are boiled with water. The solution thus obtained is filtered and the silk worked about in it for half an hour. It is then wrung out, washed in the river, dried, and finished. A BLACK DYE.—This most important color is obtained as follows ; 1 BLUEISH-BLACK.—Todye 10 lbs.of silk blueish-black 2 lbs. of alum are dissolved in 20 lbs. of boiling water. This solution is then added to a sufficient quantity of cold water. The silk is then introduced, worked about some time, and allowed three hours in the solution. Meantime $ lb. of sulphate of iron is dissolved in water, and the solution added to a bath of irarm water, and the silk, removed from the alum bath, is introduced into it. It is worked about here for a quarter of an hour and then washed. The dyeing bath is prepared as follows: Five pounds of logwood in powder or small chips are placed in a bag and boiled in water until all the coloring matter is extracted. The bag with the wood is then removed from the water, and a decoction added consisting of lb. of barrel soap in water. Having added the needful quantity of water, and varied the temperature of the bath so that the hand can be put into it without injury, the silk is introduced and worked about in it for twenty minutes. It is then washed and finished. If the color is etill not dark enough the silk must be immersed in a fresh logwood bath. -------------- Demand for Immigrants In tbe South. The following extracts are from the work on " Cotton culture and the South," noticed under the head of " New Publications :" " No possible growth in the labor now there can answer the cry which comes from all sides for' more capital, more labor ; money to build up towns, to establish factories and railroads ; money to buy more and better stock and tools ; men with brains and energy, and muscle to work them.' " Expressions like the following repeat themselves in almost every letter we receive, and ft'Oin ev"ery JSortion of the country : " 'Black laborers seem to be pasffiiig away ; we need capital, capital, capital, and reliable labor ; I must acknowledge the blacks a?e greatly improving in thteir hftbitfe of industry, if we could keep mean northern people d$af ftw* ttefflj wte totes-lent? them with fektlsas t*Jeip " ' Immigrants are wanted by all, and from every quarter ; mechanics, artisans, and workers of all trades,—men to till the soil.' " ' Honest, industrious, and intelligent laborers are needed, and good fertilizers, good and improved tools and capital; un til we are supplied with intelligent labor, we can make but little improvement in farming. Negroes know very little about the use of machinery, and are too careless to be entrust* ed with it. We have no caterpillars or army worms here in Tennessee.' " 'We need everything but land and climate,—capital, man. agement, and ambition, muscle—in other words a plenty of the article, " live men." The soil and climate call loudly for workers.' CHINESE LABOB. " With rsgard to Chinese labor, time and actual trial alone can prove whether it be practicable and economical. The dangers of the coolie system are its turning into a system of permanent peonage or slavery—systems which the old world is discarding, not entirely from motives of right, but also from conviction that they are the worst economy, adverse to both the social and material progress of the communities in which they exist. If men are to be treated as mere tools, perhaps slavery, through the selfish interest of the owner, secured the better care for that health and comfort which went so far to make good the working trim of his slaves ; but the voice of the people has been decisive on this subject in the late war, and no system, we believe, can ever be permanently inaugurated in this nation except under laws securing to all laborers the privileges of freedom. If ever coolies are introduced we may be sure there will be the strictest legislation relative to contracts,—legislation resembling perhaps the English, but in no respect permitting the abuses existing under the Spanish or French laws. " As citizens we may, however, question the expediency of flooding the country with a population, which—if we may judge, we trust without harshness, from what we have read and have gathered from conversation with those who have had actual experience with this class of labor—though it would contribute vastly to the labor force, might bring with it many demoralizing vices that could only be a tax upon the moral force of the country. " But, in treating the cotton question purely as one of economic science, and not in its connection with morals, it must be admitted that so far as their qualifications as laborers are concerned, there is probably no race so well fitted to meet all the requirements of cotton cultivation as the Chinese. " Cotton requires persistent industry, nimble and dexterous fingers in the picking season, and the crop is made more by saving than by hard labor; all these needs are exactly met by the Chinamen. At the same time he will live in the most satisfactory manner upon rice and other vegetable food, all of which he can raise while cultivating the cotton crop, and he will thrive in the climate of the river bottoms, which, whatever may bo claimed for the uplands, cannot be said to be conducive to great vigor on the part of white laborers. " Such being the facts, when we consider that the fertile cotton fields of Arkansas, Louisiana, and Texas, have never yet been cultivated in cotton to the extent of two acres in each hundred ; that these fields have been brought by the Pacific railroad within sixty to eighty days distance of an un limited supply of labor, and that this distance can be bridged at small expense, it would seem strange indeed if supply and demand did not respond to each other. " It may be added that the Chinese laborers who have built the Central Pacific railroad, were procured under contract, which did not come within the prohibitions of our coolie law, but they came over under a system of advances well secured by those who promoted their immigration, but which left the laborers to all intents and purposes free. "An Ingenious Invention, An invention has been produced in Paris for settling disputes between cab hirers and cab drivers, which seems to deserve attention. According to the account of it which we have received from a correspondent, the " compteur mecha-nique," or calculating machine, not only reckons the distance traversed, but indicates as well the exact sum of money due to the driver. Two dials are fixed on the back of the driving seat ; one contains a clock, while on the other the distance traveled is indicated by a hand acted on by the wheels ; it is entirely beyond the control of eithercabby or his "fare." The apparatus is put in and out of gear by the lowering and raising of a lever bearing the word " libre" which is only visible when the cab is empty and the " compteur" consequently unemployed. There is no danger of the driver omitting to lower this lever as soon as he is hired, it being evidently his interest to have the greatest possible distance paid for ; while, on the other hand, it would be useless for him to try to make a fictitious fare by driving about with his " compteur" in motion, for a card in the interior of the machine registers the distance traversed during the day, and the money to be accounted for to the cab owner. The great difficulty has hitherto been to find a means of marking the time spent in visits, shopping, blocks in the streets, etc., when the wheels and the tell-tale are necessarily at a standstill. M. Bruet, the invent or of the new register, has now overcome this difficulty by an ingenious contrivance, by means of which as soon as the wheels cease to act on the indicator, the clock which forms part of the machine, keeps the tell-tale hand moving at a rate which credits the driver with eight kilometers (about five miles) an hour, or two francs, according to the Paris tariff. THSl term freestone has been applied to any etone Which Ban bti wrought with the flmllet and chisel oi' mw, In tWfl eomrtif U is pepttkrly applied to terawa ssftdstoiWi