386 EXPERIMENT STATION RECORD. 



It is claimed that this machine first hauls in and stacks or loads the trees 

 and logs, then pulls the stumps, hauls them in, and stacks them ready to be 

 burned. A tract of 5 acres is said to be clearable at one setting. On a piece 

 of clearing done on heavy clay land with pine stumps from 10 to 40 in. in 

 diameter and averaging 44 stumps per acre, the machine pulled, skidded, and 

 piled about 110 stumps per day at a cost of about 28 cts. per stump, or $12.32 

 per acre. 



Beport on fires occurring in threshing separators in eastern Washington 

 during the summer of 1914, I. I). Cardiff et al. ( Washington Sta. Bui. 117 

 (1914), PP- 22). — Attention is called to the large number of fires which occurred 

 in threshing separators during the threshing season of 1914 and extensive 

 investigations as to the cause of such fires and their prevention are reported. 



There was no significant distribution of the fires geographically or with 

 reference to time of day. The season in question was unusually dry with low 

 humidity and low soil moisture content, which conditions are said to have 

 contributed to an unusually low moisture content in the grain and straw, thus 

 increasing its combustibility and making it more easily broken up by the thresh- 

 ing machinery. The same dry condition was found to have also contributed 

 to an increase in the normal amount of static electricity developed by the cyl- 

 inder and other portions of the machinery. 



Smut was found to be exceedingly inflammable owing to the fact that the 

 individual spores are very small and contain from 4 to 5 per cent of oil. It 

 was found in investigations upon the possibility of ignition of an air and smut 

 mixture from electric sparks that a spark of static electricity very readily 

 ignited the smut-air mixture, producing the same type of explosion as with a 

 flame. This was possible even though the electric spark was rather small. It 

 was also found that the amoimt of smut in wheat during the season was con- 

 siderably above that of previous years. 



It is thought reasonably certain, therefore, that the flres were caused by a 

 combination of conditions, namely, an exceedingly dry season, an unusually 

 large amount of smut, an increased amount of organic dust from broken grain 

 and straw, an increased combustibility of both smut and dust, and an increased 

 amount of static electricity. 



As regards remedies, it is stated that fire can be greatly retarded by the use 

 of so-called fireproof paints and caustic potash, and that, although too much 

 reliance can not be placed upon them, fire extinguishers will aid in retarding 

 a sudden fire. As preventive measures machine owners and farmers are 

 strongly urged (1) to ground the cylinder of the separator by means of an 

 electric brush connected by wire to an iron peg driven a foot or two into the 

 ground, (2) to provide every machine with a system of water sprinklers, 

 (3) to place a quantity of water in barrels or other receptacles near or upon 

 the separator and provide buckets for its distribution in case of fire, (4) to 

 break a couple of furrows around the setting before threshing is commenced, 

 (5) to connect in all cases the separator with the engine by means of a strong 

 cable, enabling it to be pulled away from the straw pile upon the outbreak 

 of fire, and (6) to give the crew definite directions as to an organized method 

 of procedure in case of fire. 



Greenhouse construction, S. C. Johnston (Ontario Dept. Agr. Bui. 224 

 (1914), pp. 29, figs. 20). — ^An investigation of greenhouse construction covering 

 the principal vegetable growing districts of the northern and eastern United 

 States is reported. The main results of the investigation may be summarized 

 as follows : 



The points to be considered in choosing the location and site for a green- 

 house plant are the increased cost of production due to long hauls and re- 

 handling, the value of good roads, the danger of low places, and the increased 



