Balance table and balance mounting, illumination 01 balances, weatherproofing, air conditioning, and tho laboratory plan of a modern indudrial setup lor tho microdetermination 01 carbon and hydrogen are described. Experiences with absorption and combustion tubes are related. Data are given on tho temperature of combudion and type of lumsco used. N AUGUST, 1943, William MacNevin of Ohio State Uni-I versity made an individual survey in order to determine what success was being attained by chemists throughout the couitry in microdeterminations of carbon and hydrogen, The response, inthe form of private communications, indicated that a rather large number were experiencing difficulties. As a result, several microchemists, including the author, were invited to present paper? on this subject rtt the 108th meeting of the AMERICAN CHEMICAL SOCIETY, suggesting solutions for the difficulties.Since Some chemists may be experiencing difficulties which can he attributed t o poor Iahoboratory setups, the fimt section of this paper is devoted to that subject. Certain features of the Iahoratories of this company, which the author believes to be of value, are demrihed. The rest of the paper deals with apparatus-absorption tuhes, combustion tubes, and furnaces. The opinions expressed are based upon experiences during the past 6 yeem in these Itlhoratories, where, a t present, approximately 55W to 6000 microdeterminations of carbon and hydrogen are done per year. The acceptable accuracy for these analyses is -0.3% deviation from the theory, although B large fraction of the results check the calculated values t o within a few hundredths of 1%. LABORATORY SETUP BALANCE TABLE AND BALANCE MOUNTING. Figures 1 and 2 show the details of construction of 8. rigid stone-top table which has proved very satisfactory. The supports consist of alternate layers of cork, brick, wood, and l a d , a combination which is excellent for darnpemng out vihratlons., The table 1s mounted drrectly on the concrete floor of the buddmg snd is spaced so that there is no contact with any wall . Flgures 1 and 3 show the method of mounting the balance. Large rubber stoppers are placed on the table and on top of these is 0.25 inch of plate glass which acts as the support for the balmce. Regulation balance feet of metal, glass, or plastic are used, but those having soft rubber cushions are avoided. Six miorochemical h?lances of various types (one Paul Bunge, Hamburg, Germany, wlth optioal . .