18 FRED M. USER 



introduction of a new tool or a markedly improved instrument. 

 Therefore great efforts toward the elimination of experimental limita- 

 tions in research seem highly justified. 



Where improvements in instrumentation must be of a radical 

 nature in order to secure a really significant advantage, it may not be 

 worth while in a given research program to struggle for a minor gain. 

 For example, the increase in resolving power of the optical microscope, 

 which was obtained at great cost and inconvenience by developing 

 quartz lenses for the ultraviolet region, represented a predictable but 

 relatively minor gain (although it is a valuable instrument for other 

 reasons). The radical improvement in resolution, amounting to 

 several orders of magnitude, was found three decades later in a com- 

 pletely different type of instrument, the electron microscope. 



The accuracy of instrument calibration in critical experiments 

 must be checked by the experimenter. The purchase of a high 

 quality instrument from a manufacturer of integrity does not relieve 

 an investigator of the responsibility of verifying the correctness of its 

 calibration. The calibration may be a function of time, position, 

 temperature, or abuse. Nominal values are often given, as for the 

 magnifying powers of microscopic objectives and eyepieces, it being 

 assumed that the user will make an adequate calibration under the 

 exact conditions employed. For many types of laboratory apparatus, 

 it is possible to have calibrations certified by the National Bureau of 

 Standards. In any event, the question of calibration accuracy must 

 be considered in all careful experiments. 



Since most research is done in locations where representatives from 

 the various branches of science can be sought for expert guidance 

 without undue inconvenience, it is regrettable that greater advantage 

 is not taken of the opportunity. By consulting more freely with 

 colleagues about the implications and the possibilities of research 

 problems, errors could be avoided and the general quality of the in- 

 vestigations improved. Certainly in an age of specialization, one 

 should have no feeling of inferiority or embarrassment in seeking the 

 help of specialists. When interested in highly specialized problems, 

 however, an investigator may well discover that the specialists that 

 he needs to consult are not available in his own institution. This 

 situation is especially liable to arise where the experimental limita- 

 tions of a method are determined by the intricate details associated 

 with recent laboratory instruments and their critical adjustment. 

 In that event, research may often be expedited by a personal visit to 



