SCIENCE— ADVERTISEMENTS 



THE WAVELENGTH SPECTROMETER has 



become an essential adjunct to the well equipped 

 Laboratory. Its convenience, accuracy and sturdy 

 construction make the Wavelength Spectrometer 

 an ideal instrument for spectrum and color 

 analysis. 



GAERTNER SPECTROMETERS embody the 

 results of upward of twenty- five years of experi- 

 ence gained in the construction of precision optical 

 instruments. 



Prompt Delivery on Standard Instruments 



Our Specially Designed 

 ULTRAVIOLET AND INFRARED SPEC- 

 TROMETERS 



are useful for many investigations. A very valu- 

 able combination in conjunction with the Wave- 

 length Spectrometer is the improved 



NUTTING PHOTOMETER 



Features : 



1— DESIGN OF THE INSTRUMENT. The de- 

 sign _ of the instrument provides for greatest 

 rigidity and permanence of adjustment as the 

 composite parts have been reduced to a mini- 

 mum by joining as many as practicable in a 

 single casting, at the same time giving the Spec- 

 trometer a graceful appearance. 



2— ACCURACY IN CALIBRATION. Greatest 

 care is taken in calibrating the wavelength drum 

 in order to insure the highest possible accuracy. 



3— EASY READING OF DRUM. The divisions 

 are sufficiently heavy and distinct and the fig- 

 ures ample and spaced to best advantage. 



4— ESSENTIAL PARTS IJ^CLUDED: 

 Protection cap for prism — 

 ' M'eling screws in tripod — 



Bilateral micrometer slit — 

 -^^n Extra high power eyepiece — are fur- 



- 9 nished with the instrument and in- 



-._ . ._:■/ eluded in purchase price. 



cm 



LABORATORY APPARATUS 



INSTRUMENTS OF PRECISION 



UNIVERSAL LABORATORY 



SUPPORTS 



. Gaertner & Co. 



5345-49 Lake Park Avenue 

 CHICAGO, U. S. A. 



3l ILI^ 



DIOCULAR 



Attachable to any standard compound micro- 

 scope and possessing many of the advantages 

 of the Mon-objective Binocular. 



The optical system in this instnmient is, in 

 all respects, identical with that employed in 

 our binocular microscopes except that a nega- 

 tive lens has been introduced to compensate as 

 far as possible for the increased tube length that 

 results from adding the binocular body to the 

 tube of the ordinary microscope. 



The characteristic features include: 

 !. Co 



P 



II. 

 III. 



IV. 



ENCER DIOCULAR NO. 449 



sse.oo 



CATALOGUE SENT ON REQUEST 

 ient adjustment for pupillary distance. 

 Dial register for individual settings. 

 Convergent tubes, giving normal vision. 

 Independent focusing of oculars. 



MANUFACTURERS 

 Microtomes, Delineascopes, Optical Glass, Telescope 

 nd Lenses, Optical Measuring Instruments, Etc. 



BUFFALO, N. Y. 



