be reached, for if, instead of selecting, as he has done, the weakest reinforced column in the entire lot and the strongest plain column, a reverse selection had been made, the strength of the plain column would have been stated as 1,079 lb. per sq. in. and that of the reinforced column as 3,335 lb. per sq. in.  If extremes are to be selected at all, the weakest reinforced column should be compared with the weakest plain column, and the strongest reinforced column with the strongest plain column; and the results would show that while an occasional reinforced column may be low in strength, an occasional plain column will be still lower, so that the reinforcement, even by this comparison, is of marked advantage in increasing strength.  In such cases, however, comparisons should be made by averages.  The average strength of the reinforced columns, even in this series, as given in Table 1, is considerably higher than that of the plain columns.

TABLE 1.—­AVERAGE RESULTS OF TESTS OF PLAIN vs.
LONGITUDINALLY REINFORCED COLUMNS.

--------------+--------+--------------+----------------

-----------------
|        |   Average    |
|Average | strength of  |
Location   |strength|longitudinally|           Reference.
of test.   |of plain|  reinforced  |
|columns.|   columns.   |
--------------+--------+--------------+---------------------

------------
Watertown  | 1,781  |    2,992     |Taylor and Thompson’s
Arsenal.   |        |              |"Concrete, Plain and Reinforced”
|        |              |(2nd edition), p. 493.
--------------+--------+--------------+---------------------

------------
Massachusetts| 1,750  |    2,370     |_Transactions_,
Institute of |        |              |Am.  Soc.  C. E., Vol.  L, p. 487. 
Technology. |        |              |
--------------+--------+--------------+---------------------

------------
University of| 1,550  |    1,750     |_Bulletin No. 10._
Illinois.  |        |              |University of Illinois, 1907.
--------------+--------+--------------+---------------------

------------
City of   | 2,020  |    2,300     |_Engineering News_,
Minneapolis.|        |              |Dec. 3d, 1908, p. 608.
--------------+--------+--------------+---------------------

------------
University of| 2,033  |    2,438     |_Proceedings_,
Wisconsin.  |        |              |Am.  Soc. for Testing Materials,
|        |              |Vol.  IX, 1909, p. 477.
--------------+--------+--------------+---------------------

------------

In referring, in the next paragraph, to Mr. Withey’s tests at the University of Wisconsin, Mr. Godfrey selects for his comparison two groups of concrete which are not comparable.  Mr. Withey, in the paper describing the tests, refers to two groups of plain concrete columns, A1 to A4, and W1 to W3.  He speaks of the uniformity in the tests of the former group, the maximum variation in the four specimens being only 2%, but states, with reference to columns, W1 to W3, that: