The writer says that the drill in question is an ingeniously contrived and practical machine which resolves very well the problem of sowing in furrows. A small share is attached directly to the seed distributing tube (see fig.) and is followed by a wheel-shaped roller, which, besides compressing the earth about the seeds, which is so useful in dry soils, assists in giving the furrows a proper shape, thus rendering them less liable to be damaged by the rain and bad weather.

With these drills sowing as with the usual drills can be carried out provided they be fitted with the usual coulters.

404 The Present State of Milk-Drying Technique.

Monatshefte für

FREUND, EMIL. Der heutige Stand der Milchtrocknungstechnik. Landwirtschaft, Year 6, Part 1, pp. 16-29. Vienna, January, 1913. Under the name "Milk-powder" the writer designates the powdery product into which whole or skimmed milk can be transformed. It contains only 12 to 14 per cent. of water; otherwise its chemical composition and taste are the same as those of milk. It appears to dissolve in water without leaving any residue and the solution possesses all the characters of fresh milk.

A great proportion of the methods known for the preparation of milk powder have found but little practical application; such, for instance, are the processes of the Rhine Food Industry company, Berlin, of the chemical Works "Rhenania" of Aix-la-Chapelle, of Dr. Knoch, Stuttgart, Küpfer and Werthmüller, of John Carnrick of New York and Robert Ellin, Vonkers (U. S. A), of the soup tabloid manufacturers, I. Maggi, etc. Dr. Eckenberg's patented process raised much interest but has not been adopted to any great extent.

The process according to Just Hatmaker's patent is widely spread in America and in France, Germany and neighbouring countries

Dr. Knoch has observed in milk powders made by this method that the albumen loses the power of dissolving and that the fat separates on the surface of the liquid.

A process that has recently appeared is that of the Dry Milk Central Works (Trockenmilchzentrale) Oskar Nicolai, Virsen, Rhineland. The mode of proceeding is the following: Well filtered milk is reduced in a suitable evaporator to a certain volume, after which it passes to the milk drying machine, which in the main consists of a small distributing roller and a large steam-heated drum; by means of a scraper-like device the white sheet of milk as thick as paper is detached from the drum and laid on a carrier which conveys it to a screw which breaks up the sheet and carries it to an elevator, whence another screw delivers it to an automatic drying apparatus. On leaving this it goes through a screening machine fitted with brushes and sieves from which it issues ready for packing and for sale.

A milk drying plant on this system is shown in the annexed figure, in which I, is the milk tank; 2, preliminary evaporator; 3, drying drum;

CONSTRUCTION

4, carrier; 5, transport screw; 6, elevator; 7, drying apparatus; 8, screening machine; 9, ventilators.

Similar to Nicolai's process is Gabler Saliter's. The drying, however, is not performed by a current of air but in a vacuum apparatus.

Lastly the Trufood process is to be mentioned; according to this the milk is first concentrated in vacuo and then submitted to the pulverising process.

From the above it appears that quite a number of methods for the preparation of milk powder are known. Whether these yield a product which may be pronounced perfect from every point of view is an open question. Anyhow some of the processes produce fairly satisfactory milk powders.

LEISI-GISLER, H. Ein praktischer Schweinestallboden. - Schweizerische Landwirtschaftliche Zeltschrift, Year XLI, Part 6, pp. 131-132. Zürich, February 7, 1913.

The basin-shaped floor shown in the annexed figure is 9 ft. 9 in. square with a fall in the centre of about 5 inches. A covered drain (a) crosses it throughout its length. An aproximately semicircular concrete or brick

rim (b) 4 inches wide and 6 in. high, divides the floor into the part for the litter (c) and the part for the droppings (d). It has been observed that pigs prefer leaving their droppings along the wall furthest from the trough (e) where the floor is somewhat higher. This fact has been considered in the arrangements of the present floor. The urine follows the outside of the

rim and falls into the drain without wetting the straw. Another advantage is that the straw, through the movement of the pigs, tends to collect in the lowest part just where the animals like to lie; consequently they always rest on the straw instead of on the bare floor.

For brood sows a wooden disk about 28 inches in diameter (f) is fastened to a post (g) reaching down from the roof to 12 inches above the lowest part of the floor. Under this disk the suckling pigs can crawl and avoid being crushed by their mother.

406

RURAL ECONOMICS.

The Limit Value of the Means of Agricultural Production as Basis for the Calculation of the Economical Limit of Outlay. SCHÖNFELD, LEO. Der Grenzwert der landwirtschaftlichen Productionsmittel als Grundlage für die Berechnung der ökonomischen Intensitätsgrenze des Aufwandes. Mitteilungen der landwirtschaftlichen Lehrkanzeln der k. k. Hochschule für Bodenkultur in Wien, Vol. I, Part 3, pp. 411-441. Vienna, January 15, 1913.

The different portions of the means of production employed have not the same value for agricultural production, for each of them, though they are equal among themselves, is utilized to a different degree. After having reached an optimum production the gross returns, and consequently the utilization and the net returns, for the same additional outlay begin to diminish, and production at last reaches a point at which the total gross returns do not increase any more by any further addition of outlay. The difference in the utilization of the portions of outlay follows the well-known law of diminishing returns of agricultural production, which is determined by three facts :

I. The production of plants on a given area is limited by the following factors which are limited to the unity of surface: space, light and air, warmth and rainfall; animal production in its turn is limited by the physical dimensions and specific productivity of the organisms.

2. According to Aereboe the character of being present in the minimal proportion may belong at any moment to any one of the factors; for the better or worse utilization of an outlay the frequent favourable coincidence of all the necessary factors of production is decisive. The number of moments however in which plants are in a position to utilize completely a considerable capital of plant food in the soil must be all the smaller the higher this capital is, the more the requirements of plants vary as to the amount and quality of their plant-food during their period of growth and the shorter the latter is.

3. The first portions of the outlay serve to build up and to maintain the substratum of production in the organism of the plant or of the animal and only the subsequent portions of outlay are utilized for transformation into the principal products.

The writer gives a graph of the relationship between the quantities of means of production employed, the limit gross returns, and the total

RURAL ECONOMICS

"

gross returns. The "limit gross return" of the total outlay is the increase of the gross return obtained by the addition of the last portion of outlay. It is to be distinguished from the real gross returns obtained by the single portions of the outlay: while the "limit gross return " in general varies for every portion of the outlay, the real gross returns, or the average gross returns or the portions of general gross returns corresponding to each portion of any outlay, are equal to each other. The "limit gross returns are used when it is a question of expending or not expending the last portion of an outlay; while the average gross returns serve for the calculation of average utilizations and the like. The writer then gives a mathematical formula showing the relation between the two values, and demonstrates further that the total gross returns may be expressed either as a product of the average gross returns by the number of portions of the outlay, or as the sum of the limit gross returns.

After having introduced the notion of "limit gross returns in cash", he arrives, with the help of integral and differential calculus and on the basis of limit gross returns, to a mathematical expression for the total cash gross returns for a given outlay. He thus shows that the gross returns may be considered as a function of the outlay.

Under "utilization value" (Gebrauchswert) of a means of production, only the cash net returns value is to be understood. This is obtained by subtracting from the increase of the cash gross returns the cost of the greater quantity of means of production used or of the further increased costs of production. It is an error to designate the utilization or the cash gross returns as the "utilization value" of a means of production, as high gross returns and a higher utilization lead to a utilization value of the means of production only when there are net returns. These however depend to a great extent upon the cost of producing the means of production.

Nor can any money value determined indirectly for any non-marketable means of production be called utilization value. From the above it appears that the cash net returns value of a certain quantity of means of production may be directly calculated with correctness by a variation experiment only when the variation is possible without alteration of the other factors which take part in the production. The correct calculation of the cash net returns value of such quantities of means of production, without which there cannot be any production, for instance the total quantity of meadow hay supplied as principal food, is theoretically quite out of the question, as in this case every experiment of variation on the total quantity is impossible. In order to ascertain the limit of intensity only the cash net returns value of those portions which are near the supposed limit of intensity need be calculated. The writer then explains the notion of the "limit cash net returns value" (grenz-geldreinertragswertes), or briefly "limit value ", which represents the increase of the cash net returns obtained by the last portion of the outlay, and he calculates this also on the basis of the "limit gross returns.

The limit of intensity can be rigorously established in figures only for means of production the cost of producing which is known. This is not

the case with those umarketable means of production used as the basis of production. With concentrated foods and chemical manures the precise limit of intensity stated in figures plays an important part. The use of a means of production for agricultural produce has reached the economical limit of intensity when it attains that point at which the cash net returns are at a maximum. In order that this should be the case all those portions which still have a positive limit value must have been employed; at the limit of intensity there is the one whose limit value = o. When therefore it can be ascertained at what stage of the outlay this portion is situated, the limit of intensity will be given. This stage of the outlay is then calculated by the writer by means of the cash gross returns and cash net returns values of the portions of outlay, and in this way he finds a formula for the exact calculation of the economical limit of intensity of the outlay.

Lastly, he determines by means of an experiment of Schneidewind on manuring sugar beets with nitrate of soda, and one of Kellner on milk yields as affected by increasing quantities of fodder, the limits of intensity of the outlay on manures and on concentrated foods respectively, as they result from these variation experiments.

407 The Profitableness of Hoed Crops.

SAGAWE, B. Die Rentabilität des Hackfruchtbaues. Fühlings Landwirtschaftliche Zeitung, Year 62, Part 4, pp. 113-128. Stuttgart, February 15, 1913.

The writer endeavours to show in this paper that it is possible by means of the inductive statistical method to find the most suitable organization and degree of intensity for the most varied conditions. In order to calculate the intensity of labour in the farm he values the percentage of the acreage devoted to meadows and forage plants at 2, that taken up by grain crops at 1, and that occupied by hoed crops, which are the most exacting, at 3. In this manner he obtains a figure which represents the intensity of cultivation (Anbau-intesitäts-zahl) characterizing a farm (1). He calculated this index number for all the farms he examined, then he arranged the farms according to these indices and observed the results of the farms in connexion with this order. The material for this work was taken from the book-keeping records of the German Agricultural Association (Deutsche Landwirtschaftsgesellschaft) and the Book-keeping Bureau of the chamber of Agriculture of the Province of Silesia. Only those farms were considered in which conditions allowed of a reduction or increase of the area devoted to hoed crops.

A superficial observation of the farms arranged according to the above index shows what far-reaching differences are caused by altered intensity of cultivation (see Table I).

(1) If for instance 25 per cent. of the total acreage is devoted to meadow and forage crops, 25 per eent. to grain and 50 per cent. to hoed crops, the index number of the intensity of cultivation will be 25 X 2 + 25 X 1 + 50 X 3 = 187.5.