LIGHT FROM THE SOCIETIES. 



317 



old pustules, and at the same time will render the germi- 

 nation of spores falling upon the surface of the plants 

 impossible. Take no diseased branches from cuttings, 

 and watch the young plants closely to destroy any signs 

 of disease. Use no soil that has become contaminated 

 with spores. At the earliest opportunity remove the soil 

 from benches that have grown diseased plants, depositing 

 it at a safe distance, fumigate the house with burning 

 sulphur to kill any stray spores, and refill the benches 

 with clean soil. Careful and persistent attention of this 

 kind will rid an establishment of the pest in one or two 

 seasons. By concerted action among carnation-growers, 

 it will be quite possible to remove all traces of the disease 

 from this country, and by vigilance on the part of im- 

 porters to keep it from again gaining a foothold. 



The use of some fungicide is almost imperative. Ex- 

 periments are yet needed to determine what is the best 

 fungicide to use and the best method of applying it. An 

 old Swiss gardener now at Richmond, Ind., is familiar 

 with the European aspect of the disease, and says it can 

 be controlled by spraying with water in which green 

 vitriol (sulphate of iron) is used at the rate of one-third 

 to one-half a pound in a gallon of water. I am inclined 

 to think that this treatment would be reasonably effective. 

 There are good reasons to suppose, however, that some 

 form of copper solution will be more effective. The 

 Bordeaux mixture is the best known, but is not so easily 

 prepared as the ammoniated copper-carbonate. The 

 latter may be bought ready for use under the name of 

 copperdine. The materials for these remedies are not 

 especially expensive, and if a suitable spraying apparatus 

 is at hand the application will cost but little in either 

 time or money. A precautionary measure after the rust 

 has appeared in a house is to keep the air as cool and dry 

 as compatible with the health of the plants, thus retard- 

 ing the growth and distribution of the spores. It is in- 

 teresting to note that some varieties are more affected 

 than others, Silver Spray proving itself particularly 

 susceptible. — Prof. Arthur, before the Am. Carnation 

 Society. 



Prof. Goessman on Manures for the Garden.— The 



cheapest form of potash in the market is the German 

 muriate, and it answers well for many crops ; it is not, 

 however, adapted to tobacco, which demands the sulphate 

 or carbonate. The latter is the chief valuable ingredient 

 in wood-ashes. Cotton-seed ashes are often very rich in 

 potash, some samples analyzing 32 per cent.; they must, 

 therefore, be applied with care. All strong chemicals 

 should be thoroughly mixed with the soil. Ashes vary 

 much in strength, and should always be bought and used 

 by analysis. Nitrogen is an essential element in a com- 

 plete manure, and almost every soil and every crop de- 

 mands it, and will pay for its application. Nitrate of 

 soda is at once the best and cheapest chemical to use ; 

 sulphate of ammonia is slower and less certain to give 

 satisfaction. Fine ground Carolina and Florida rock, 

 known as "floats," and the tine ground guanos, as well 

 as the Thomas slag, which crumbles of itself into an im- 

 palpable powder, constitues a better application in gen- 



eral than the dissolved bone or dissolved phosphatic 

 rocks, because, being very cheap, the farmer can afford 

 to apply them liberally, and their effect will last for many 

 years. The Thomas slag has a great future before it, and 

 it is likely to be produced in immense quantities at the 

 smelting furnaces. Garden vegetables have shown that 

 the muriate of potash was the best form of potash for 

 cabbages, but failed with lettuce, and was not good with 

 celery. By far the best results with tomatoes and pota- 

 toes were obtained with the sulphate of potash . — Boston 

 Market-Gardeners' Association. 



Principles of the Evaporation of Fruits. — Fruit will 

 cook in water at 212°, or bake in an oven at 225^, but if 

 the air circulates fast enough the fruit will not cook or 

 burn or even become heated at the temperature of 300°, 

 for the evaporation of water is a cooling process. The 

 air in motion, together with the heat, causes the fruit to 

 dry rapidly. The chemical changes which belong to 

 truly evaporated fruit will now begin, and the albumen 

 is coagulated precisely the same as in an egg when boiled. 

 All the fruit-jelly remains in the cells or is left upon the 

 surface by the evaporation of the water in which it was 

 dissolved. The germs of animal or vegetable life are 

 destroyed by the high heat. It is by these changes and 

 uniting a part of the water already contained in the fruit 

 with the fruit- starch, that the truly evaporated products 

 are rendered more wholesome, more digestible, less 

 perishable, and consequently more valuable. — Geo. A. 

 Davis, before a Farmers' Institute. 



Adulteration of Copper Mixtures.— Copper sulphate 

 in the form of large crystals may be regarded as being 

 fairly pure, but when in the form of powder it is always 

 safe to test its purity. Copper carbonate, on account of 

 its rather high price, and also on account of its powdered 

 condition, is probably quite liable to adulteration, and 

 should always be tested. While the help of a chemist is 

 needed to tell how much copper a substance contains, 

 the following suggestions will enable anyone to test cop- 

 per sulphate and copper carbonate as well as Paris green 

 in regard to their purity : Copper sulphate, if pure, 

 should dissolve completely in water, making a clear so- 

 lution, free from sediment or suspended matter. Copper 

 carbonate should dissolve completely in nitric acid, com- 

 monly called aqua fortis. If it does not dissolve com- 

 pletely, it is impure and probably adulterated. Copper 

 carbonate, if pure, should dissolve completely, or very 

 nearly so, in a considerable quantity of strong ammonia- 

 water. Both tests should be used. Of course, copper 

 carbonate could be adulterated by using powdered cop- 

 per sulphate, but this adulteration could easily be 

 detected, since copper sulphate easily dissolves in water, 

 while copper carbonate does not. Paris green should, if 

 pure, dissolve completely in strong ammonia-water, used 

 in liberal quantity. Such simple tests as the foregoing 

 may be applied by anyone, and they will serve as a fairly 

 reliable guide regarding the purity of the compounds 

 mentioned. When adulterants are added they have been 

 found by common experience to exist in the form of 

 some finely powdered white substance, as barium sul- 



