Illustrative Exhibit A "was taken to show the instrument as it is used. Illustrative Exhibit B "was taken with the cover plate taken off, to show the essential portions of the mechanism."

It was stipulated that the instrument in question is composed in chief value of base metal not plated with platinum, gold, or silver, or colored with gold lacquer.

The witness testified he used this instrument constantly in his work in the university, and that "this instrument is constructed to facilitate the measurement of the wave length of light emitted by any type of light-emitting source"; that it makes such measurements "to an accuracy of about one-thousandth of a millimeter"; that the real purpose of the instrument "is to obtain accurate wave lengths of spectrum lines"; that it has "no utility whatsoever"; and "it is a scientific problem purely and simply", being used only in the witness' research work in his room; that it is being used by a student of his at the present time "in the measuring of the spectrum of a star"; that the part of this instrument which produces this great accuracy is the screw; that the instrument has also certain optical parts, consisting of the microscope marked "Y" on Illustrative Exhibit A, and “X”. two reading microscopes; also a condenser lens, which is not shown on Exhibit A. It appears that the purpose of this micrometer is purely scientific, and that there are "no practical results at all"; that "it would be known as pure research in physics" and "is actually pure research in spectroscopy." In response to the court's question the witness testified "it is used entirely in pure science", and "it is never being put to any practical purpose."

It was testified that the screw, as to which extreme accuracy is necessary, is the most valuable part of the instrument; that the value of the optical parts is comparatively minor, being about twelve per centum of the value of the instrument; and that the remainder of the value of the instrument "is mainly the screw.'

It was shown that the microscope "Y" "is used for observing the line", and "it gives you a magnified image of the photographic plate which you have in front of you." The instrument cannot be used without the microscope, but "the feature of the micrometer is that it shall measure", the name "micrometer" meaning "that it shall measure small distances accurately by means of a screw", and not by means of the microscope. The two eyepieces at the other end "are to enable one conveniently to make a reading on the position of that disk 'V' which is attached to the screw." Such reading can be made without the eyepieces, and they are not necessary.

* * *

It appears that some micrometers are used in industrial laboratories "for the measurement of spectrum plates", where the measurement has to be extremely accurate; that the micrometer at bar is more

accurate than those used in industrial laboratories, as "in no industrial laboratory do they require this accuracy.' The witness was asked the following question:

R Q. The instruments that are used for practical purposes are they just like this, or do they differ?

He answered:

A. They could be like this. This instrument could be supplied by Hilger to an industrial laboratory. This instrument was supplied to us.

The witness indicated that the result obtained by the use of the micrometer at bar "is one essential step" in a scientific process, "which runs from the source of light back to the information regarding the atoms which were in that light."

This closed the testimony for the plaintiff.

Defendant's witness Rayton is an optical engineer for the Bausch & Lomb Optical Co. of Rochester, N. Y., manufacturing "practically all kinds" of optical instruments, selling at wholesale throughout the United States. He testified that he supervised the designing of optical instruments and is familiar with micrometers.

The plaintiff "concedes" that this instrument is not a micrometer. The witness testified that "micrometers in general are used to measure dimensions of some kind or other"; that the fact that "one micrometer measures one degree finer than another" does not change its general character, but "it might change the specific application." This was a conclusion of the witness not based on any fact.

The witness was shown "A General Catalogue of the Manufactures of Adam Hilger, Ltd.", and his attention called to the description of "Hilger Measuring Micrometer with 6" (150 mm.) travel (reading to 0.1 micron, and reading by double verniers) L 18" (page L 3 catalogue). He testified that this description corresponds with his understanding of the instrument at bar.

The portion of this catalogue relating to micrometers L 13 and L 18 was marked "Illustrative Exhibit D" for identification.

The witness confirmed the testimony of plaintiff as to the necessity of the microscope in the instrument at bar by stating it is absolutely essential to the use of the instrument, and that without the two microscopes at the end a reading could be made, as they were "just merely an additional aid to increase the accuracy." As to the use of micrometers the witness testified:

They are used for measuring linear dimensions of all kinds. One case is the manufacture of motion-picture films, the measurement of the location and dimensions of sprocket holes. Another application is in the measuring of the separation between the lines of the spectrograph. It might be used for checking the accuracy of linear scales of any kind.

These uses of micrometers are "intensely practical", and "all three of those applications I have mentioned are made of it in industrial enterprises." They are also used, he testified, in pure science for measurement purposes.

On cross-examination the witness admitted he had never seen Illustrative Exhibit A, and his opinion was entirely based on "reading the catalogues"; that his testimony as to the degree of fineness, to which the instrument at bar is calibrated is based on "nothing more than the manufacturer's statement"; that, while he did not know of his own knowledge whether it is used principally in pure science, in laboratories and colleges, or principally in applied science, he had "a very clear opinion on it." He also testified that micrometers vary a great deal in construction and price, and that the difference in price is "very largely" caused by the minuteness and the care with which the instrument is constructed.

Mr. Bowen, United States examiner of merchandise, testified for the defendant that among other things he examined "scientific optical apparatus"; that Illustrative Exhibit D for identification was "a catalogue that I found in the office when I assumed the examination of this class of merchandise. It was one of scores of other catalogues"; and that it was the catalogue that the Government uses as an aid in the examination of merchandise.

Mr. Townsend, an engineer with the Bell Telephone Laboratories "in charge of the precision measurement work", testified that for approximately 19 years he had been engaged in the use of scientific instruments for measurement purposes; that he had used micrometers as follows:

Briefly, I have used two types of micrometers: Screw micrometers, which are used as end measuring micrometers; and optical micrometers, which measure the distance between two marks or lines scratched or otherwise marked on a surface.

He testified that whether a micrometer contains a microscope or not depends entirely on the precision or accuracy of the instrument; that the optical micrometer measures the distance between the two lines; that a line has width, and the finer the mark indicating the line "the more accurately you can measure the distance between two points; so that in very accurate instruments one must draw a fine line. * * * Consequently, if you must read on a very fine line it is essential that some magnifying glass, or microscope, or other optical reading instrument be employed." In such a case a microscope is an essential feature of the instrument.

The witness testified he had used instruments of the type shown in Illustrative Exhibits A and B, and that there is "no essential difference" between the instrument at bar and those he had used; that he