April 9, 1920] 



SCIENCE 



367 



It may be noted here that the undersigned 

 was at least partially instrumental in awaken- 

 ing interest in the unsatisfactory official rules, 

 the result being that both the Bureau of 

 Standards and the homologating body sent 

 representatives to Europe with a view of 

 putting the rules on a fairer and more scien- 

 tific basis. 



The outcome is that the rules are greatly 

 improved but are still open to proper criti- 

 cism and objection. It is necessary, however, 

 for all either to accept the rulings of the 

 official body or, if they are to be ignored, for 

 all to work on the same unbiased scientific 

 basis and abide by the decisions of an author- 

 itative and independent scientific laboratory 

 such, for example, as the Bureau of Standards 

 at Washington. 



In order to bring out clearly an important 

 point in this matter, that is, the importance 

 of the air temperature correction, assume that 

 two identical perfect barographs with no in- 

 strumental errors are taken up, one in the 

 summer time and the other in winter, to such 

 an altitude that both read say 8 inches of 

 mercury as the minimum pressure. Assume 

 also that the average temperature of the air 

 is in the first case — 10° C. and in the second 

 — 30° C. which values correspond closely to 

 actual observed figures. 



The true altitudes corresponding to this 

 pressure are in the first case 33,475 feet and 

 in the second 30,929 feet, although the alti- 

 tude uncorrected for air temperature is the 

 same for both, i. e., 36,020 feet. These figures 

 are obtained from Circular No. 3 of the Aero- 

 nautic Instruments Division of the Bureau of 

 Standards and are within J i>er cent of the 

 true values. The correction for the iirst case 

 is — 2,545 feet and is twice as much for the 

 second, or 5,091 feet. The value 36,020 feet 

 assumes that the air is at a uniform tem- 

 perature of — 10° C throughout. As stated 

 above Eohlfs' record reduced in this manner 

 by the Bureau of Standards gave a true alti- 

 tude of 32,450 feet. 



We now quote from the Air Service Ifews 

 Letter No. 11, issued by the Information 

 Group, Air Service, of March 9, 1920. 



The purpose of this letter is to keep the person- 

 nel of the Air Service both in Washington and in 

 the field informed as to the activities of the Air 

 Service in general and for release to the public 

 press. At an indicated altitude of 36,000 feet 

 . . ., the temperature at his greatest altitude was 

 67 degrees below zero F. . . . The preliminary cali- 

 bration of the barograph indicates that the air- 

 plane reached a pressure of eight inches of mer- 

 cury which corresponds approximately to 36,000 

 feet on the Bureau of Standards altitude chart. 



In commenting on this letter we note that 

 it does not claim that a record was obtained. 

 We ask then by whose authority a record is 

 granted and published as such. We note also 

 that approximately 36,000 feet corresponds al- 

 most exactly to the stated minimmn pressure 

 of eight inches of mercury, which shows that 

 this value has not been corrected for air 

 column temperature. The ground temperature 

 is not stated but the Weather Bureau kindly 

 furnished us with the values, max. + 18° F., 

 min. + 13° F. for Dayton, Ohio, February 26, 

 1920. Using the most favorable value, i. e., 

 + 18° F., for the McCook Field flight, the 

 average is — 31.4° C, which gives a correc- 

 tion, using the Bureau of Standards tables of 

 — 5,269 feet and hence the true altitude is 

 not 36,020 feet (as published) but is 30,751 

 feet. 



This altitude does not reach that of Eohlfs 

 by 1,700 feet, figured on the same basis, and 

 as according to the rules for beating a record 

 it should surpass it by 328 feet (100 meters) 

 it lacks 2,027 feet to beat Eohlfs' record. 



It is not surprising then that the Curtiss 

 Company wished to protest the validity of 

 this new record. The premature announce- 

 ment in the press that Major Schroeder has 

 beaten all altitude records with a flight to 

 36,020 feet, beating the previous one held by 

 Eohlfs, is neither justified by the figures, nor 

 authorized by the Army bulletin nor fair to 

 the Curtiss Company's machine and motor 

 nor just to its pilot, Mr. Eohlfs. Slightly 

 modified results were given personally to the 

 writer at a meeting which he had with Major 

 Schroeder, showing an uncorrected altitude 

 of 36,118 feet and a true altitude of 30,835 

 feet. 



