OCTOBEB 30, 1908] 



SCIENCE 



615 



Lamiaer to any desired depth or until its upper 

 edge is level with the surface of the soil. 

 This method has objections. For example, 

 the core of soil within the frame is generally 

 more or less compacted during the process of 

 sampling. Por this reason, the sample of soil 

 does not possess unchanged physical char; 

 acteristics, and hence it can not be used to 

 advantage in a study of many of the more 

 important physical properties of the soil. 



A method of sampling which more closely 

 meets the requirements of the soil physicist, 

 who desires to determine the permeability of 

 soil to water or air and to study other phys- 

 ical properties, has been proposed by Whitney, 

 and is described by Wiley in the following 

 words: 



An excavation two feet square and eighteen 

 inches deep is made in the soil. On one side of 

 this hole the sample of soil or subsoil is secured 

 by means of a narrow saw blade and a sharp 

 carving knife. The sample of soil should be two 

 inches square and from three and a half to four 

 inches long. It is placed in a brass cylinder three 

 inches long and three and a quarter inches in 

 diameter. The open space in the cylinder is filled 

 with paraffin heated just to its melting point. 



This method, also, is open to objections. In 

 the first place, it is often difficult to secure an 

 unbroken core of soil to a considerable depth, 

 and, further, the sample which is taken by this 

 method is too small for many lines of study. 



The writer with the assistance of M. W. 

 Pullen, of the Engineering Division, Iowa 

 State College, has devised a sampler by which 

 he has largely overcome each of the objections 

 referred to in the preceding paragraphs, and 

 is enabled to take, in a comparatively short 

 time, a core of soil, three inches in diameter 

 and of any desired depth up to about fifteen 

 inches, which possesses every physical char- 

 acteristic of the soil in the field. This ap- 

 paratus makes it possible for the operator to 

 quickly and easily secure a large sample of 

 soil for mechanical and chemical analyses. 

 For this purpose it promises to prove more 

 useful than some of the devices which are 

 now employed. However, the new sampler is 

 especially adapted for taking samples of soil 

 for the determination of volume weight. 



moisture content, water-holding capacity, 

 permeability to water or air, capillary move- 

 ment of water and other physical character- 

 istics. The sampler has been tested in many 

 different types of soil. No particular diffi- 

 culty has been encountered except in coarse 

 gravel and in heavy soils which were very 

 wet. When the soil is in a condition favor- 

 able for crop growth, a sample of soil three 

 inches in diameter and ten or twelve inches 

 in length may easily be secured by two opera- 

 tors within six or eight minutes. A single 

 operator finds it somewhat difficult to get a 

 sample. However, an experienced man, by 

 using a spade two or three times to remove 

 the soil from the sides of the machine, has 

 secured samples without undue exertion. 



The total weight of the sampler, exclusive 

 of the wooden frame, is twenty-six pounds and 

 it may be transported from one point to 

 another with little difficulty. 



During the past year a large number of 

 laboratory determinations have been made 

 with samples of soils which were taken with 

 the new sampler. The data secured are for 

 the most part very satisfactory and are of 

 such a nature as to justify the conclusion that 

 the sampler will prove of value whenever a 

 study is made of the physical properties of 

 soils. 



The new soil sampler is not complicated 

 and may be made by any first-class mechanic 

 in a well-equipped machine shop. The 

 sampler consists of an outer cylinder of steel, 

 fitted at the lower end with two sets of cutting 

 teeth of tool steel; spiral grooves are milled 

 on the outer side of this cylinder which serve 

 to give increased cleaning capacity to the 

 sampler. 



A steel cylinder, with an inside diameter 

 of a little more than three inches and with a 

 guide rod nineteen inches in length, fits 

 snugly within the outer cylinder. This inner 

 cylinder does not turn with the cylinder which 

 carries the cutting teeth, but is held rigidly 

 in place by a key. If this cylinder were to 

 turn, the core of soil would be broken and 

 would thus be rendered useless for a deter- 

 mination of certain physical properties of the 

 soil. A cylinder made of heavy galvanized 



