From this the conclusion was drawn that when low grade ammoniates are used for making base goods by the « wet process », a large percentage of the nitrogen is rendered highly available for plant use.

All the above results were the work of a committee appointed by the directors of the Agricultural Experiment Stations of the New England States, New York, and New Jersey to investigate by laboratory methods the availability of organic nitrogen.

20 The Fertilizer Trade in the Netherlands.

Communication from the Netherlands General Direction of Agriculture.

The General Direction of Agriculture, Division VI (Publications and Statistics), has compiled expressly the following table concerning the present condition of the production, importation, exportation and consumption of fertilizers in the Netherlands.

Production, importation, exportation, and consumption of fertilizers in the Netherlands in 1910.

To this table, which gives a good idea of the fertilizer trade in the Netherlands, the following information may be added as to the method used in obtaining the above data.

The total consumption of nitrate of soda was calculated by subtracting the amount exported from the quantity imported.

The production of sulphate of ammonia was estimated in 1907 at 10 000 metric tons. In comparing the amount purchased by the co-operative societies with the total consumption, the latter seems too high, perhaps on account of an error in the estimate of the production. In fact, according to a communication made to the International Institute of Agriculture by the

"Gemeente Gasfabrieken Hoofdkantoor," the production of the gas factories alone does not exceed 5 293.39 m. t. (1910).

The total consumption of potash salts and of basic slag has been estimated in the same manner as that of nitrate of soda. According to the data of the German "Kalisyndicat," the consumption of potash salts in 1910 was 178 000 m. t.

Some years ago, the annual production of superphosphate was estimated at 120 000 in. t., but a new factory having since been started, the present output may be reckoned at 150 000 m. t. There is a discrepancy in the importation and exportation figures, but this arises from the fact that they include much raw phosphate. Nevertheless, as the total consumption of superphosphate was estimated some years ago at 60 000 m. t., if these figures were correct, 90 000 m. t. is not too high an estimate for the present consumption.

21 - Phosphates and Nitrates in Egypt. Their Importance to European Agriculture.

1. POLIER. La richesse agricole et minérale de l'Egypte. § 3 Les richesses minerales de l'Egypte. 8. Phosphates et Nitrates. Bulletin de la Société d'Encouragement pour l'Industrie Nationale, Vol. 118, No. 2, pp. 232-272 (268-270). Paris, August, September, October 1912.

· Die Wichtigsten

2. STUTZER, O. Phosphate, Sonstige Phosphatlagerstätten Afrikas. Lagerstätten der "Nicht-Erze", First Part, pp. 363-364. Berlin, 1911. The discovery of large deposits of phosphate and nitrate in Egypt would be a very important matter, not only for Egyptian agriculture, since constantly increasing quantities of fertilizers are imported into the country, but also for the European agriculturist, who makes use of enormous amounts of these substances.

Nitrates. These have to be left out of consideration, for though large deposits of nitrate have been discovered in the Nile valley, the high proportion of sodium chloride they contain renders them useless. Further, they do not form crystalline masses, but are simply saliferous clays. The result of prospecting seems so far to be negative.

Phosphates. The phosphate deposits, on the other hand, appear likely to be a source of wealth to the country. Their presence has been observed at a large number of places all situated in a zone which, on the west of the Nile, includes the oases of Dakha and Kharga, while on the east it leaves the Nile between Keneh and a point south of Esneh, and stretches to the north-east up to the Red Sea, at Safadja and the west coast of Sinai. Outside this broad band, phosphate deposits have been found in the oasis of Baharia and quite to the south-east of the frontier of Egypt in the valley of Wady Hodein, on the shores of the Red Sea.

The principal known deposits are the following:

1. The first was discovered in the Nile valley II miles south of Esneh. A second was found on the plateau called Djebel el Qurm; this is 0.6 to 1.2 miles wide by 51⁄2 long. The nearest station is 6 miles

distant, but connection with the railway could easily be effected. A third deposit is at Sebahia. The samples taken have yielded 70 % of tribasic phosphate.

2. An English Company has obtained concessions at Safadja on the shores of the Red Sea, but as no details of results have been divulged, the probabilities are that they have not been of a satisfactory nature.

3. The richest deposits are without doubt those of Rachid, in the Daklah Oasis. They extend throughout the whole length of the latter for a distance of at least 31 miles. The average thickness of the workable stratum varies from 6 to 10 ft. The bulk of the deposits occurs always on the edge of the desert on the borders of the cultivated land, and their exploitation would be a very easy task. Unfortunately, the Oasis of Daklah is in the open Libyan desert 370 miles from the Nile Valley. But lately the railway has been carried as far as the Oasis of Karghah, which is only 93 miles from that of Daklah.

Thus it is at Daklah that the prospects of Egyptian phosphates appear most brilliant. They have not escaped the notice of the Gafsa Phosphate Company, who are known to possess a quasi monopoly of the trade.

22- New Methods for determining the Comparative Value of Selected Plants.

1. HUMMEL, A. Massenanbauversuche. - Illustrierte Landwirtschaftliche Zeitung, Year 31, Nos. 88 and 89, pp. 821-824 and 829 + figs. 922-924. Berlin, Nov. 4 and 8, 1911. 2. BILGER, O. Zur Methodik der Sortenprüfung. Ib., YEAR 32, No. 91, pp. 827-829 +figs. 898-900. Berlin, Nov. 13, 1912. Formerly, selected seeds were tested in the laboratory; now on the contrary, experiments made in the field are considered the most satisfactory. This has given rise to the development of comparative cultivation experiments of the new selected varieties, e. g. those carried out by the German Agricultural Society (Deutsche Landwirtschafts Gesellschaft), which have risen in number from 562 in 1905, to 726 in 1911. Of these 164 in the former year and 250 in the latter were devoted to oats.

The principal difficulty in such experiments is the avoidance of experimental errors, which prevent an exact estimation of the productivity of the new varieties. In Denmark and in Sweden, where such experiments are much practised, they are repeated on the same soil for from 3 to 8 years in succession. The new method proposed by Hummel and named by him the "compensation method" has the advantage of giving more immediate results, and consists essentially in the two following calculations:

1) Take the arithmetical mean of the results in absolute figures for every variety; to this, taken as 100, the results obtained from every plot of the same variety are referred, and thus all the results are given in percentages of the arithmetical mean for every variety submitted to experiment.

SELECTION.

2) Take successive groups of 9 contiguous plots forming a large square, find for each group the arithmetical mean of the results referred to 100 as above; the difference between this figure and 100 represents the mean deviation of the square from the average of the whole experiment field. Then add this amount to the figure of the central plot, or subtract it, according as to whether it is negative or positive, and repeat the operation for all the plots.

The percentages thus corrected are recalculated in absolute figures, and to these the calculation of the probable errors is applied by means of the formula:

where

is the sum of the separate results, d the difference between the separate results and the average, and n the number of the plots for every variety, 0.845 being a constant.

Now, calculating the probable error (by means of such a formula) in the direct experimental data and that in the data obtained by the proposed method, it will be found that this last is less.

In fact, in the practical case of the two comparative experiments made with 30 varieties of beans in a series of 6 lots and with 20 varieties of rape in a series of 5 lots, the probable average error for the whole experiment was reduced respectively from 9.19 to 6.90 and from

4.48 to 3.54 in percentage of the average. In conclusion, the advantages of the new method proposed would be: I. By means of the "compensation compensation" calculation, part of the experimental errors which are inherent in comparative cultivation experiments are eliminated, and the sources of error are thus limited to those dependent on the separate lots.

II. Such errors as cannot thus be eliminated, are expressed in figures; thus the results can be subjected to mathematical criticism.

III. Selection having for its object the increase in the yield of cultivated plants, is thus placed upon a surer and more fitting basis.

23- Cultural Bud Mutations of Solanum immite Dunal.

Comptes

HECKEL, ED. Mutation gemmaire culturale du Solanum immite, Dunal. Rendus de l'Académie des Sciences, Vol. 155, No. 18, pp. 804-806. Paris, Oct. 28, 1912. After referring to his previous researches on the mutations of Solanum tuberosum L., a species growing wild in Bolivia and Peru, the writer gives the results he obtained with Solanum immite Dunal, which was brought by M. Verne from Chancay (north of Lima, Peru), that is the classic habitat of this species. In Chancay a complete mutation in the tubers and all the subterranean portions of the plants was obtained, although the tubers had only attained a slight degree of development (10 to 12 gr. maximum); further, the productivity of the plant appeared previously to be very small, for two specimens only bore 3 tubers; the

latter however showed mutations. The writer did not consider the arguments for making Solanum immite a separate species sufficiently conclusive, and after having cultivated it a long time, he believes it should be regarded as identical with S. tuberosum L.

Its behaviour under cultivation (intensive fertilizing) as regards the mutation of its tubers, shows other points of similarity with S. tuberosum.

The mutation found in the latter occurred in one year, and this is the first time that M. Heckel has observed such a rapid change, which was at the same time far-reaching, affecting the various parts of the tubers and the stolons, which are very plentiful in the wild plant. In other cases, the mutation was slower, and attended by greater difficulties; sometimes in fact it did not occur (Solanum Comersoni and S. Maglia). The fact of the rapidity of mutation in the tubers in the type S. tuberosum and in S. immite Dunal perhaps explains the classic attribution of all cultural varieties to the wild S. tuberosum L. of Peru. This variety has no doubt accommodated itself to cultivation and to the production of edible tubers more readily than other wild species, and so quickly that it has been given the preference in cultivation over other kinds.

Once it has given rise to a mutation, it appears to produce varieties, which have tubers of different colours and shapes. This will be seen next season, in which all the tubers, both mutated and non-mutated, from the crop of 1912 will be used.

The writer obtained mutation in S. Maglia and S. Commersoni under conditions which show the slowness and the difficulty of this change. No mutations have so far occurred in the tubers of S. Jamesii Torray, which has been cultivated for three years.

24

Solanum immite, a New Species of Potato from Peru. DENEUMOSTIER, CHARLES. Le Solanum immite, nouvelle espèce de Pomme de terre alimentaire du Pérou, Annales de Gembloux, Year 22, Part 11, pp. 621-624, 6 plates. Bruxelles, Nov. 1, 1912.

Sr. N. Esporto, Botanical Assistant at the National Agricultural and Veterinary School at Lima, found in the lomas (1) of Pasamayo, prov. of Chancay, from 1906-1907, the species of Solanum which has a tuberous rhizome and which had been found for the first time about 1790 by Pavon, and been preserved in de Boissier's herbarium. It was determined by Dunal, who gave it the name of S. immite and considered it to be a distinct species. This Solanum was much sought after by the North Americans especially and it was regarded with interest as the possible origin of a new edible potato.

Selection and improvement experiments were carried out on this species at the Lima School and the results obtained showed that the yield and the tubers (weight and size) were capable of improvement.

(1) Lomas winter pastures on the high parts of the spurs of the Andes.