132 DEPARTMENTAL REPORTS. 



In view of the phenomenal success of the introduction of Sumatra 

 leaf into the Connecticut Valley, and the control of black rot in the Penn- 

 sylvania crop, there have been many urgent demands for help in the 

 tobacco industry in New York, Ohio, Wisconsin, Texas, and Florida. 

 Preliminary steps have been taken to meet these demands, but they 

 are so great that it will take considerable time to extend help even 

 where it is most needed. Active measures are being taken, as 

 announced in my last report, for investigating the possibilities of 

 growing Havana tobacco in Texas, and it is aimed to make this exper- 

 iment one of the strong features of our work for the coming year. 



It must not be overlooked that there is pressing need of investiga- 

 tions in the manufacturing and export types of the Southern States, 

 and there have been many requests for such help on the part of the 

 Department. It has seemed wise, however, to confine our attention 

 to the highly organized industry in the production and handling of the 

 cigar types and get this work well established before the other types 

 are taken up. Just as soon as possible, however, the Virginia, North 

 Carolina, Tennessee, and Kentucky districts will be attended to. Pre- 

 liminary work is being done in several of the States in the construc- 

 tion of soil maps of the important tobacco areas, and plans are being 

 perfected for the improvement of the types and grades of leaf grown 

 there. 



During the spring of 1901 a comprehensive exhibit of leaf tobacco 

 was installed at the Pan-American Exposition in Buffalo, modeled 

 somewhat after the exhibit at Paris, although necessarily much 

 smaller, as the space at our command was considerably less. 



Another important line which has been taken up is in the securing 

 of tobacco seeds for Congressional distribution. Contracts have been 

 made with leading growers in the various States to have seeds saved 

 from vigorous, healthy, well-bred plants, and arrangements have been 

 perfected for the distribution of these varieties to the districts to 

 which they are particularly adapted. It is believed that this will 

 be a great improvement over 1$ie former miscellaneous distribution of 

 tobacco of all kinds to all districts. 



LABORATORY OF SOIL PHYSICS. 



The work of the physical laboratory includes the investigation of 

 the physical properties of soils and their economic bearing, the phys- 

 ical examination and mechanical analysis of the soil types established 

 by the field parties, and the preparation and testing of the apparatus 

 used in the field work. 



THE REMOVAL OF SALTS FROM SOLUTIONS BY SOIL GRAINS. 



It has long been known that finely divided solids have the ability 

 to condense upon their surfaces a small proportion of the dissolved 

 substances contained in the solution with which the solid is in contact. 

 This property is known as ''adsorption," and is an important factor 

 in the conservation of plant food in the soil, since it prevents the 

 rapid leaching away of the soluble materials and their consequent 

 loss to the groAving crops. This property has never been fully investi- 

 gated, and it seemed very desirable to subject it to accurate measure- 

 ment and determine how important this property is in the economy of 

 nature. For the preliminary work crushed quartz rock in a very fine 

 state of division was selected on account of its slight solubility, 



