CHEMICAL DIVISION.

The work accomplished in the Chemical Division up to the 27th of May, 1879, was included in the annual report for 1878. From that date to the present time there have been made

First. Ninety-one miscellaneous analyses, including soils, waters, fertilizers, clays, ores, marls, and other mineral substances.

Second. Thirty approximate analyses of various food and medicinal materials.

Third. Two hundred and seventy-four analyses of various sugar-yielding plants and their juices.

Fourth. Five experiments in alcoholic distillations from the refuse of sugar-manufacture, and twenty-eight experiments in making sugar from various sugar-yielding plants-in all thirty-three.

The experiments entered upon for the purpose of determining the amount of sugar in the juice of the several varieties of sorghum, of the stalks of maize and of pearl millet, give results which enjoin their earliest possible publication that they may reach the farmers for their instruction before the time for the spring planting arrives.

A fair conclusion from these investigations appears to be that there exists but little difference between the various kinds of sorghum as sugar-producing plants, and that the juice of each of them is at a certain period of its development nearly as rich as that of the best tropical sugar-cane grown in this country.

It is a matter also of extreme practical importance that it should be known that this period of maximum content of sugar is maintained for a sufficient time to enable the manufacturer to work up a large crop of stalks. Another result of this investigation has been to satisfactorily explain the cause of repeated failure in the production of sugar from certain plants during the past quarter of a century.

For the purpose of making clear the above points, a few of the results obtained by the chemist are appended. The varieties of sorghum canes subjected to this investigation were "Early Amber," "White Liberian," "Chinese," "Honduras," and "Pearl Millet."

Beside the above there were made very many examinations of other specimens of sorghum, and also of cornstalks.

These examinations confirm the general principle above stated, viz., the practical equality and great value of each variety of this plant.

In the following table is given the result of the analysis of each of the plants in four successive stages of development. It will be observed that the amount of glucose (or uncrystallizable sugar) diminishes and the amount of sucrose (or true cane sugar) increases up to a certain time in the development of the plant; that these plants differ widely as to the time when the sucrose is at its maximum, but are alike in this, that the maximum is obtained at about the same degree of the development of the plant, viz., at full maturity, as indicated by the hard, dry seed and the appearance of shoots or suckers at the upper joints of the stalk.

It is also to be observed that the heavy frost of October 24, which was sufficient to form ice half an inch in thickness in tubs of water, did not produce any marked diminution of sugar. Three varieties of sugarcane received from Louisiana in excellent condition, and which doubtless fairly represent the average character of this famous sugar-plant, were analyzed and the analyses are embraced in this table for purposes of com parison.

Something over 23 tons of the stalks of corn, sorghum, and millett have been used in making investigations, the result of which has been not only to fully confirm the work of last year, but also to aid in the settlement of certain other questions of the highest practical importance. In other cases it has been found that the quality of sirup obtained has been precisely such as the previous laboratory analyses of the juices used made probable.

The average of the nine best sirups obtained showed a percentage of cane sugar present equal to 92.7, being a loss of 7.3 of the amount orig. inally present in the juice, while the average of the nine poorest, i. e., containing the lowest percentage of cane sugar, showed a percentage of

cane sugar present equal to 90.1, a loss of 9.9 of the amount originally present in the juice.

This very satisfactory result, showing as it does conclusively the pos sibility of securing from the juices all the cane sugar present without a loss of more than 7 to 10 per cent., is of great importance in view of the fact that all these juices were evaporated in an open pan. A few of the experiments made give a reasonable basis for estimating the probable yield of sirup and sugar to the acre, and therefore an approximate estimate of the cost of producing sugar.

Below is the tabulated result of a few of the experiments from stalks grown upon the grounds of the department.

These stalks were grown in rows three feet apart, twelve to fourteen inches in the row, and although a good crop, there is no doubt that upon good land an equal yield to the acre could be readily obtained.

The first and second columns give the result actually secured, but the several juices were not in their best condition as compared with the results given in the first table. The third column is the amount which this same weight of stalks would have yielded had they been cut at the proper time. The juice obtained from the stalks by the imperfect means at the command of the department was a little more than onehalf of the amount present in the stalks. The fourth column represents the results obtainable by the use of a mill that would have given 68 per cent. of the juice, a result which is possible and claimed as common by the manufacturers of the mills. There is no doubt that when the present industry shall have received the employment of the capital and scientific ability which has developed the beet-sugar industry, even these results, which may appear extravagant to many, will be equaled and probably surpassed.

Although as has been stated these sirups were obtained from stalks in which the maximum content of sugar had not been developed, yet they all crystallized well and yielded an excellent article of sugar.

The sugar had not been separated from the Chinese sorghum sirup, which gave 54.7 of sugar, nor from the field corn, which gave 39 per cent. of sugar.

The experiments with field corn are worthy of special notice, since the results secured are not only most surprising, but contrary to almost universal belief.

The corn-stalks were of three varieties, viz., Lindsay's Horse Tooth, White Improved Prolific, and White Dent, three coarse-growing white field corns. The stalks grew in drills three feet apart and about nine or ten inches in the row.

The ears were plucked after they had thoroughly ripened and the husks were dead and dry; the stalks, however, were yet juicy. The corn was plump and sound and yielded at the rate of 69.1 bushels of shelled corn, fifty-six pounds to the bushel, to the acre. The stalks were then topped, stripped, and crushed, and the juice proved to be the best yet obtained from corn-stalks at any period of growth or of any variety. It is exceedingly to be regretted that this department had not during the past season an opportunity to try these experiments in the large and practical way of field cultivation which would have been befitting the importance of the occasion. Not less than an acre, and preferably five acres, of each variety of sorghum and maize experimented with should be grown and its developments should be watched carefully with the aid of all the appliances of science, throughout the season and worked up at the proper time with the best machinery attainable, and it is hoped that a matter of so much importance will receive such attention at the hands of Congress as will enable the department to properly discharge its duties to the country in this regard.

With the present grounds and laboratory force at the command of the department this is impossible. The correspondence upon matters pertinent to the Chemical Division has increased so largely that with the present force it is impossible to give it the attention which it demands. The amount of work which has accumulated in advance of the means to accomplish it shows how promptly and gladly our people would avail themselves of the advantages which a proper enlargement of the division would afford. The legitimate work which has already accumulated and which is mapped out for the Chemical Division would employ the present force for years.

ENTOMOLOGICAL DIVISION.

On the retirement of Prof. C. V. Riley, May 1st, the department was fortunate in obtaining the services of Prof. J. H. Comstock, of Cornell University, concerning whom the President of the university, Hon. Andrew D. White, wrote:

He seems to me in every respect fitted to discharge the duties usefully to the public service and satisfactorily to yourself. He has most thorough scientific attainments, great energy, pleasant address, excellent temper, and is certainly destined soon to be a recognized authority in his department throughout the world as he now is over a considerable part of this country. Nothing but a sense of duty to him leads me to write this letter. As it is, I hope to reclaim him some day. As to character, temper, relations with scientific people, he is all that could be desired.

It is sufficient to say that Professor Comstock's studies have fitted him for the position, and under his direction the Entomological Division has made notable advance in its appropriate investigations, and thus far the high recommendation of President White has been entirely sustained.

The work of the Entomological Division during the year may be classified under four heads:

1. Finishing the investigation of insects injurious to the cotton plant, begun last year under special appropriation of Congress, and preparing an extended report upon its results.

2. Rearing to the perfect stage new or little known injurious insects for the purpose of gaining a knowledge of their habits and transformations which shall facilitate the suggestion of remedies.

3. The conducting of an extended correspondence relative to noxious insects.

4. The raising of different varieties of silk-worms with a view of experimenting: first, upon the most approved methods of rearing; and, second, upon food-plants, carefully comparing the Osage orange with the different varieties of mulberry. Also the distribution to all appli cants.

The investigation of insects injurious to the cotton plant has been completed. Professor Comstock, having been engaged in this investigation from its beginning, was able to take charge of it without material loss of time. A trained observer was sent into the field early in May, where he remained until the middle of September, carrying on extensive experiments upon remedies and clearing up mooted points in the life histories of the cotton-worm and the boll worm.

Work on this report has been rapidly progressing, and it is hoped and believed that the facts therein contained will enable the Southern planters to render these enemies to their staple crop sources of much less damage than heretofore.

As regards the rearing of new or little-known injurious insects, the division has studied since May 1 the following:

Many of these insects are treated of in the annual report of the entomologist. Others will require the additional study of another season,