672 



SCIENCE 



[N. S. Vol. XXVI. No. 672 



In 100 Pounds 



The maintenance values of feeding stuffs 

 will seldom require more than two integers for 

 their expression in the new unit and the pro- 

 duction values, I think, never. Expressed in 

 this way, these values have quite the appear- 

 ance and effect of percentages. It is true that 

 if expressed per 100 kgs. instead of per 100 

 pounds the numbers would be somewhat un- 

 wieldy, but the actual adoption of the metric 

 system in this country still seems distant. 

 The reason for expressing the values per 100 

 pounds instead of per pound will appear if we 

 consider the use of these figures in the com- 

 putation of rations. 



As a simple case let us suppose we have a 

 ration consisting of 12 pounds of timothy hay 

 and 18 pounds of com meal, and that we 

 desire to compute its production value on the 

 basis of these tables. 



The ordinary method of computing the 

 digestible nutrients is illustrated in the first 

 half of -the subjoined table. The calculation 

 is identical with the one with which we are 

 already familiar, with the single exception that 

 the number of pounds of the feeding stuff is 

 expressed as a fraction of 100 pounds. In 

 other words, the transposition of the decimal 

 point is made in this number and not in the 

 figures for the percentages. 



The second portion of the table shows the 

 computation of the ration on the basis of its 



energy value. But a glance is needed to show 

 that the two are precisely similar and that 

 the units of energy can be handled in this way 

 in a manner precisely analogous to the man- 

 ner in which protein, carbohydrates and fat 

 are handled. 



The total ration, therefore, would be as 

 tabulated in the second table. 



Computed Ration 



12 lbs. timothy hay 

 18 " corn meal 



Dry 



Matter 



10.20 lbs. 

 15.30 " 



25.50 " 



Digestible 

 Proteids 



0.19 lb. 

 1.04 lbs. 



1.23 " 



Production 

 Value 



3.10 T 



12.73 " 



15.83 " 



Finally it should be noted that it is not the 

 relative value of these two methods of ex- 

 pressing the content of feeding stuffs or 

 rations which is here in question. Assuming 

 the desirability of the use of units of energy, 

 the purpose is to show that the manner of 

 using them according to this scheme is quite 

 similar to the familiar methods of computing 

 rations, so that the transition from one system 

 to the other should be comparatively easy, 

 while the use of large figures is avoided. The 

 writer would be grateful to receive the fullest 

 criticism, both in general as regards the utility 

 of such a unit and specifically as to the suit- 

 ability of the one proposed and the propriety 

 of the name suggested. 



Henry Prentiss Armsbt 



State College, Pa. 



THE FLYING MACHINE 



The fact that a machine of the aeroplane 

 type built entirely of metal and canvas may 

 be made to fly by the power of an ordinary 



