86 EXPERIMENT STATION RECORD. 



Land clearing-, A. J. McGuire {Minnesota Sta. Bui. 134, pp. 32, figs. 22). — ^The 

 only practical methods of clearing land of stumps in use by farmers in northern 

 Minnesota are said to be blasting and the use of the horsepower stump puller. 

 The stump puller is considered most economical for small stumps, while for 

 stumps so large that they can not be handled and burned when they are pulled, 

 blasting is said to be best. " For very large stumps or green stumps the com- 

 bined use of explosives and the stump puller gives the most satisfactory re- 

 sults." For the lowest cost and quickest results it is suggested that all trees 

 and brush be removed at one time and a pasture or meadow established to 

 keep down brush and bring returns. Green stumps over a foot in diameter 

 should not be removed unless immediate cultivation is necessary as they may 

 be removed more readily after a few years and the soil will be in a better 

 condition. "When an explosive is used it should be placed under that part 

 of the stump which will offer the greatest resistance, usually the center. The 

 depth at which to place the explosive under the stump may generally be esti- 

 mated by the diameter of the stump at the ground line." 



"For removing stumps from clay or clay loam soil the lower grades of 

 dynamite, 25, 27, and 30 per cent are quite equal to the higher and more ex- 

 pensive grades, 40 and 60 per cent. They are cheaper, less dangerous, and 

 leave the soil in better condition." It is claimed that an explosive known as 

 "virite" is being used successfully when the soil is not wet. It is said to be 

 somewhat cheaper than dynamite, does not produce headache, and does not 

 freeze. "A pound of explosive should be used for each foot of diameter of the 

 stump, if it has been cut some time. From 1* to If lbs. per foot in diameter 

 should be used for green stumps." 



Dynamite is said to work best in wet soil when the earth is thoroughly 

 tamped over, if care is taken not to tamp directly on the dynamite. Virite 

 requires a soil free from water and must not be compressed at all as it will 

 not explode, so that only the upper part of the hole should be thoroughly 

 tamped. 



The methods of priming, blasting, and firing charges are reviewed and 

 warnings given as to the danger of improper procedure and carelessness. In 

 this connection, it is suggested that before using dynamite methods of 

 handling it be studied and that, if possible, an experienced man be employed 

 for a day or two as an instructor. 



Vitrified brick as a paving- material for country roads, V. M. Peirce and 

 C. H. MooREFiELD {U. 8. Dcpt. Agr. Bui. 23, pp. 34, pls. 10, figs. 3).— It is the 

 purpose of this bulletin " to furnish information relating to the construction of 

 brick roads and to supply suggestions for aiding engineers in preparing specifica- 

 tions under which such work may be satisfactorily performed." 



The principal advantages of brick roads are stated as follows: (1) They are 

 durable under heavy traflic conditions, (2) they afford easy traction and good 

 foothold for horses, (3) they are easily maintained and kept clean, and (4) 

 they present a very pleasing appearance. The principal disadvantage is the 

 high first cost. One of the most essential features is stated to be the selection 

 of the brick, and in this connection a brief discussion of raw materials and proc- 

 esses of manufacture, general physical characteristics of the perfect finished 

 product, and field and laboratory tests is given. 



In the construction of brick pavements or roads the essential features to be 

 considered in preparing the subgrade are enumerated as (1) thorough drainage, 

 (2) firmness, (3) uniformity in grade and cross section, and (4) adequate shoul- 

 ders. Brick pavements should be supplied with strong durable curbings of 

 stone, Portland cement concrete, or vitrified clay shapes, both on the sides and 



