3. Laboratory of agricultural, vegetable and bromatological chemistry. [Illustration: FUMIGATING CAOUTCHOUC.] 4. Laboratory of microbiological and technical agriculture. 5. An agricultural and floral museum. 6. A corridor for machines. 7. A meteorological station. Sole Paragraph. A station that may be established in a region where there already exists a federal institution of similar kind, pertaining to agriculture in general, the installations above mentioned shall be reduced to numbers 5, 6, and 7 and shall be provided with a small laboratory for the mechanical analysis of the soil, and utensils and instruments necessary for the proving of seeds of useful vegetables, so that a choice or selection may be made and their identity, purity, quality and germinating energy may be verified, including in these experiments those which refer to plants that are injurious. Art. 17. To accomplish the ends proposed, the experimental stations ought to: 1. Attend the consultations that may be held upon any agricultural question in their line. 2. Execute gratuitously analysis of fertilizers, spices, plants and water, when required by the nearest federal institute, when it does not possess the necessary laboratories. 3. Distribute selected plants and seeds. 4. Study the diseases common to the plants cultivated and the means of combating them, and explaining these things to those interested. 5. To publish yearly and distribute free of charge a bulletin devoted to the relation of the works done and the useful knowledge acquired relative to agricultural and rural industrial subjects, and especially the results obtained as to the most practical and economic method of cultivating the trees that produce rubber, and the most profitable subsidiary plants, as well as the best methods of the treatment, conservation and packing of the products. Art. 18. There shall be admitted to the experimental stations, persons who wish to gain a practical knowledge in any of the sections, at the discretion of the Director, who shall fix the number of students in agreement with the chief of the respective section. Sole Paragraph. On equal terms, apprentices between 15 and 18 years of age, shall be admitted, the numbers to be determined by the respective Director, with the approval of the Minister, who shall have daily tasks corresponding to their capacity and aptitude. The Director in the name of the Minister shall give a certificate, on which shall be indicated the work that has been done, to all those who have completed their apprenticeship. Art. 19. The plan of each station shall be organized to meet the peculiar necessities of the zone in which it may be established, conserving, however, the principal fundamentals already set forth.