366
JOURNAL OF CHEMICAL EDUCATION
F EBRUARY , 1930
As an example of a volumetric precipitation method, they may run either Mohr's or Volhard's method for chlorides, standardizing the silver solution against NaC1. For neutralization methods, an HCl solution is standardized against NalCOa; and a NaOH (carbonate-free) solution is prepared by diluting a concentrated NaOH solution (in which NazC03 is insoluble), and standardized against the HCl. They are then used to determine an organic acid, protein in flour, and inorganic phosphates. For oxidation-reduction methods, a permanganate solution is standardized against sodium oxalate, and used to determine calcium. Sodium thiosulfate is standardized against potassium dichromate in acidified potassium iodide solution; iodine solution is standardized against the thiosulfate or against arsenious oxide; and the two are used to determine formaldehyde in formalin. Finally, a bromate-bromide solution is prepared and standardized by weighing a definite amount and making up to the mark in the volumetric flask. Then i t and the thiosulfate are used to determine the phenol in a phenol solution. All except the flour, organic acid, and chloride samples are delivered in liquid form; and the students analyze aliquot portions. If desired, the stock sample solutions can be prepared in such a way that the mass delivered can be calculated by multiplying the volume by some simple integer. The students still get enough use of the balance in standardizing solutions, but all congestion is relieved. With the liquid samples, administrative work is greatly, simplified, and grading is more certain. In this new course, no work is given, which is not applicable to medical clinical work, yet fundamental principles have not been slighted.
UNITED STATES CIVIL-SERVICE EXAMINATIONS The United States Civil-Service Commission announces open competitive examinations for ASSOCIATE AGRONOMIST (Sugar Beets), 53200 to $3700 a year and ASSISTA N T AGRONOMIST (Sugar Beets), $2600 to $3100 a year. Applications must be on file with the Civil-Senice Commission a t Washington, D. C., not later than February 12th. The examinations are t o 5U vacancies occurring in the Bureau of Plant Industry. Department of Agriculture, for duty in the field. At present there is a vacancy in the associate grade at Bellingham, Wash., and there are vacancies in the assistant grade a t Huntley, Mont.. and Fort Collins, Colo. Competitors will not he required t o report for examination a t any place, but will be rated on their education, training, and experience, and on a thesis or publications filed with the Commission. Full information may be obtained from the United States Civil-Service Commission Washingon, D. C., or the Secretary of the United States Civil-Service Board of Examiners a t the post office or customhouse in any city.
