matter. Messrs. Gayou and Millardet were the first to turn their atten. tion to investigating copper in wines, and in a preliminary work have shown that the metal occurs only in the most minute quantities, often less than 0.1 milligram (= .015432 grains) to the liter, and sometimes not even a trace can be detected, the copper being eliminated during the process of fermentation. In a second series of analyses the same chemists experimented simultaneously upon wine, pickett*, and pomace. For wines, the quantity does not exceed 0.1 milligram (=.015432 grain) per liter (= 1.760773 pint). The largest quantity in pickett is 1 milligram. Pomace contains a larger proportion, 26 milligrams (=.4 grains) per kilogram (=2.6803 pounds Troy). About the same time Messrs. Crolas and Raulin presented to the Academy of Science an account of analyses made for the same purpose and the figures obtained support the preceding experiments. The wines analyzed yielded from 0.1 to 0.3 milligram per liter; for the picketts or sweet wines the same as in the other analysis, while the pomace and the lees gave from 40 to 70 milligrams of copper (=three-fifths to 1+ grain) per kilogram. Other analyses made by Messrs. Muntz, Carles, Ravizza, etc., have confirmed these results. In the meantime (1886) the Administration of Agriculture, wishing to call forth a uniform work as authority for subsequent researches, invited professors from different departments of ag riculture to collect samples of wines obtained from vines that had been subjected to different treatments. The wines were sent to the laboratory of technology of the Agricultural School of Montpellier where M. Bouffard, professor of technology, subjected them to a rigorous analysis. The figures obtained are of practical importance, for they represent various kinds of wines and furnish means for comparing the actions of different methods of treatment. We can not dwell here upon the details which were published in the Bulletin of the Minister of Agriculture, but it will be interesting to note the average amounts of copper obtained in a few of the twenty-four departments from the sixty-six specimens for analysis. This is what we find: * Pickett, term used to designate wines made from the pomace of grapes. Drome.. Rhone Drome.. Copper, in milligrams, per liter of wine-Continued. SECOND TREATMENT, WITH EAU CELESTE (M. AUDOYNAUD). Nothing.. 0.1 Nothing 0.15 Nothing .do THIRD TREATMENT, WITH COPPER SULPHATE PURE. The conclusions drawn are as follows: First. For the treatment with Bordeaux mixture upon fifty-nine samples, the averages are found to be as follows: Second. For the treatment with eau celeste the average amount of copper is 0.15 milligrams. Mons. Bouffard adds, in conclusion, that the weight of copper found in wines or other liquids, taken even at its highest estimate, is so slight that it is safe to assert that hygienically considered the treatment by copper sulphate is not injurious to health. Notwithstanding the slight traces of copper detected by the authors already mentioned it has been asked if the proportion of copper is not increased in rainy seasons, which would necessitate frequent applications to the grapes themselves. To answer these questions we made the following test at the last vintage. In a vineyard of Jacquez attacked by the mildew we se lected six vines in each of three rows. The row A, was treated with Bordeaux mixture, Millardet's formula (8 kilograms of copper sulphate and 15 kilograms of lime); the row B, with eau céleste, M. Audoynaud's formula 1 kilogram of copper sulphate and 1.5 kilogram of ammonia); the row C was left for compar ison. About the 1st of August, one month before the vintage, the bunches of grapes in the rows A and B were treated so thoroughly that they had the appearance of having been immersed in the copper mixture. This was repeated each week, but after the last treatment a violent rain somewhat washed the fruit. They were sprinkled again as copiously as at first five days before the vintage, so at time of gathering the grapes they were very strongly marked with copper stain. The row C had received three ordinary treatments with eau celeste. The grapes of each row had been gathered separately and taken in flagous to the laboratory to ferment. After eight days of fermentation the clear wine was drawn off and bottled. We give in the following table the result of the analysis. To be more exact each test was verified twice. Copper, in milligrams, in a liter of wine. No. Where produced. Treatment. Amount of copper. 1 École d'Agriculture.. A. Bordeaux mixture, five applications. Very Less than 0.1. 5 Bourbonne-les-Bains.. Eau celeste, four treatments; Berrichonne mixture, Trace. one treatment. The preceding figures are sufficient to reassure any one as to the amount of copper contained in wine. Indeed if one considers that numbers one and two, in which the grapes at the time of fermentation were thickly covered with a coppery stain, gave when analyzed only 0.5 milligram of copper per liter, as a maximum, we may conclude that in ordinary cases, where only the usual treatments are given, the wine would contain only an inappreciable quantity of copper. It is evident from the analysis that the copper is eliminated during fermentation, since the lees.contain a considerable quantity. Different theories have been advanced to account for this phenomenon. Then after as many more days the analysis for copper was made. The method of analysis employed was the same as that followed in the preceding experiment-the Riche process, which consists in isolating the copper from the ashes of wine by electrolysis. A liter of wine was reduced to ashes; the ashes were treated by sulphuric acid and submitted to a current from a Bunsen pile; the copper was deposited in a metallic state at the negative pole, represented by a plate of platinum. To estimate the proportion it is dissolved in a drop of dilute sulphuric acid, treated with ferro-cyanate of potassium, which gives a yellowish-brown coloration with salts of copper, and is then compared with the wines previously tested. The analysis was made not only from the wines obtained for this experiment but also upon two other samples from different provinces. One of these samples came from a vine in the suburbs of Montpellier (Augnelongue quarter), treated with eau celeste. The second was sent to the laboratory by the Society of Viticulturists from Bourbonne-lesBains (Haute-Marne), for investigation, rumors of poisoning by the metal in the wines having become current in this region. This wine was made from a Gamay vine which had been treated four times with eau celeste (same formula as before) and had received a fifth application, one month before the vintage, of Berrichonne mixture (Dr. Perdregeon), viz, 3 kilograms of copper sulphate, 4.5 kilograms of sodium carbonate, and 1 liter of ammonia in 200 liters of water, using 400 liters per hectare (= 2.5+ acres). According to Messrs. Gayou, Millardet, and Perret the copper oxyde, dissolved in the "must" by the acids of the grapes disappears during fermentation under the form of copper sulphide, especially when a treatment with sulphur was added to that of the salts of copper. M. Quantin has, by some interesting experiments, shown that in alcoholic fermentation certain organisms can act upon the sulphates usually found in must and transform them into hydrogen sulphide. In presence of copper, hydrogen sulphide forms copper sulphide which is precipitated in the lees and pomace. Other chemists claim that the copper would be precipitated by the tannin of the grape under the form of copper tannate. At present the lack of definite experi ments forbids a decision in favor of any hypothesis. It is sufficent to know, as has been clearly proven, that the clear wine after fermentation contains but an unimportant trace of copper. Besides this, a series of experiments made in 1886* by M. Magnien, of the School of Agricult ure, show that by simple contact with the vessels, casks, stop-cocks, tubings, etc., in the various manipulations of wine-making, the quantity of copper oxyde dissolved might equal this amount. In certain cases it might exceed the average shown in the preceding table. We have tried to prove by these facts that the wines manufactured from vines treated with salts of copper ought not to be considered unhealthy. The largest quantity of copper which the wines could contain is always inferior to the amount found in ordinary food, since an adult could take nearly 1 milligram of copper each day. To attain this quantity it would be necessary to drink daily nearly 10 liters (=17} pints) of wine containing an average of 0.1 milligram of copper per liter. We think this would rarely occur. Believing we have said enough upon this subject we shall be glad if by these remarks we have been able to dissipate any doubts which might still exist upon the question of the injurious effects of copper in wine. * Recherches chimiques relatives à l'action du vin sur les métaux usuels, par Magnien. Messager agricole, août 1876. S. Alum, use of, in preparation of fungicides...... Ammonical solution of copper carbonate: (a) and (b) mixtures of... Adherence to fruit of.. Apple scab treated with Brown-rot of grapes checked by use of Downy mildew treated with Early application of, necessary. Following Bordeaux by in treating black-rot Injury from, in treatment of apple scab....... More effectual than other solutions in treating apple scab Ammoniure of copper as a remedy against Peronospora of the vine Amount of copper in wines... Anthracnose Bordeaux mixture as preventive of Copper sulphate no effect on... Cost of treatment of....... Dusting of lime as a remedy against.... Dusting with sulphur in prevention of...... Eau celeste mixture unsuccessful in prevention of.. First appearance of.... Iron sulphate in treatment of.. Unsuccessful treatment of.... Wet season favorable for.. 91 8 .7, 41, 50 58 44 18 44 44 16 16, 18 76 16 43 |