EXPERIMENT STATION REPORTS. 175 



anaiij^ciuenl.s hy havin<»' this air compressor and lank put on tlie niacliiue 

 at the lime of purchase. 



The author has found the following advantages in the use of the lool : 



It does the work of opening ca\''ities, pruning away stubs, cutting 

 off broken splintered limbs — the work which at ]>resent requires the 

 mallet and chisel — very effectively. 



It must be confessed that the ordinary fruit grower, other than saw- 

 ing as close as is possible, makes no attempt to make wounds flush, this 

 tool, since it renders this work easier, should do much to encourage a 

 better class of pruning. 



It does the work of four or five men and the work of holding the 

 l»noumatic hammer is not so tiring as the use of the mallet and chisel. 



It is an excellent means of cutting out limb cankers such as are made 

 by pear blight. New York apple tree canker and the like. Rightly 

 used, it shoubl save many limbs wliich otherwise would be girdled in 

 a short time. 



(liven to a city forester or a park board, it will make possible the 

 repair of the trees of a whole street where, at jji'^sent, only a few 

 blocks can be handled. 



The cost of this outfit, as used in this experiment, which gives air 

 enough for the o])eration of two small hammers, is about one hundred 

 dollars, exclusive of the engine. This estimate places the hammer at 

 from |;?r).00 to 140.00, depending on size; pump at |34.00; the tank at 

 |15.00, Avilh the hose at twenty cents per foot. 



The number of hammers to be operated from one air supply and the 

 size of ]»ump, engine, etc., must be decided for each particular case. 

 Furthermore, the chisels, gouges, etc., must be fashioned to suit the 

 particular class of work to be done. 



The author wishes to thank the Chicago Pneumatic Tool Company of 

 Detroit for the loan of the tools used in the experiment and the De- 

 partment of Farm Mechanics for assembling the outfit. 



In conclusion, it may be well to point out that this use of the pneu- 

 matic chisel is new and is as yet in the experimental stage. This tool 

 does the work of the chisel and mallet, not that of the axe or saw. As 

 tried on trees on the M. A. C. campus and in an apple orchard nearby, 

 it did very efficient work. It would seem that the recommendations 

 in light of this experience were justified and it is hoped that the tool 

 will find a wide use. 



Prof. E. A. Bessey, East Lansing, Michigan. 



Dear Sir — I have the honor to submit herewith a report of the Plant 

 Physiological studies for the year 1912-13. Outside of the time used 

 for instruction, my work has been entirely on the Adams Fund work. 



The problem in its broadest sense is a problem of Nutrition. The role 

 of salts in the growth and development of plants is obviously a highly 

 important problem. Of the class of organic foods we know much but 

 as to the function of the other class, salts, we know very little beyond 

 the fact that neither ])lants nor animals can live on an ash free diet. 

 Botanists and soil chemists have assumed that salts are of nutritive 

 value since the elimination of one or more elements from the solutions 

 interfers Avith the vital activities of the plant. Animal physiologists 

 have recently shown that some salts function in a protective w^ay rather 

 than in a nutritive one. Not only is this true for some few marine 

 animals but also for a few plants. 



