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ATLAS OF ABSORPTION SPECTRA 
 
 le) 
 
 H. S. UHLER and R. W. WOOD 
 
 
 
 WASHINGTON, D. C.: 
 Published by the Carnegie Institution of Washington 
 
 May, 1907 
 

 
 CARNEGIE INSTITUTION OF WAS i] 
 ~ PUBLICATION NO. 71. 
 ¥ 
 * 
 4 PRESS OF THE WILKENS-SHEIRY PRINTIN 
 WASHINGTON, D. C. 
 
 
 
INTRODUCTION. 
 
 
 
 By R. W. Woop. 
 
 
 
 In spite of the very large amount of work which has been done on ab- 
 sorption spectra, there exists practically no collection of photographed spectra 
 from which one can pick out the media most suitable for any particular line 
 of investigation. The greater part of the published records are drawings 
 made from visual observations, and give no information regarding the optical 
 properties of the media in the ultra-violet. It seems desirable therefore to 
 compile a set of photographic records which are free from the errors liable 
 to enter into observations made by visual methods, and to arrange them in 
 such a way that the medium or media necessary to secure a desired result 
 could be readily found from a mere inspection of the plates. 
 
 A great deal of experimental work was necessary before satisfactory 
 photographic records were obtained. The details of the spectrograph and 
 the refinements of the method have been worked out very skilfully by 
 Dr. Uhler, who has done practically all of the experimental work. It was 
 our original plan to include the colored salts of metals, and to examine a 
 large number of colorless substances for peculiarities in the ultra-violet. The 
 solutions of the inorganic compounds could not, however, be investigated 
 in precisely the same manner, owing to their less powerful absorption. Much 
 thicker absorbing wedges were required, and these gave trouble, even when 
 compensated, as a result of dispersion. It was therefore decided to limit 
 the present work chiefly to a study of the aniline dyes, which are used toa 
 much greater extent than the metallic salts, in the preparation of absorbing 
 screens. The absorption spectra of a number of metallic salts, however, 
 have been photographed, as it is believed that many of them will be useful 
 in the preparation of ray filters; some of them are far more transparent in 
 the ultra-violet than the aniline dyes. Even such substances as the salts 
 of erbium, neodymium, and praseodymium are useful in special cases where 
 it is desired to suppress one or more isolated spectral lines. For example, 
 a solution of neodymium has a very narrow and intense band coincident with 
 the D lines, and has therefore the property of cutting out the sodium radia- 
 tion from a given source, transmitting at the same time nearly the whole of 
 the remainder of the spectrum. _ The same salt can be used to advantage 
 when working with the new cadmium and zinc arc lamps in quartz tubes, 
 
 A 
 
 Y 
 
2 ATLAS OF ABSORPTION SPECTRA. 
 
 made by Heraeus. The fact that the absorption of each substance in the 
 ultra-violet is recorded, makes the plates of especial value to any engaged 
 in the preparation of screens for spectroscopic or photographic purposes. 
 
 For the removal or transmission of one or more isolated lines some 
 other arrangement is often more useful than an absorbing screen. A 
 spectroscope with a slit placed in the focus of the observing telescope 
 (monochromatic illuminator) is frequently all that is necessary. But if more 
 light is required, the following device may be used. A block of quartz from 
 2 to 4 cm. in thickness, cut perpendicular to the optic axis, is mounted 
 between two Nicol prisms. The transmitted spectrum is crossed by black 
 bands, which result from the rotatory power of the quartz. By adjusting 
 the nicols and varying the thickness of the quartz it is often possible to get 
 rid of the spectrum lines which are not desired, and at the same time to 
 utilize the whole area of the source, which can never be done with the spec- 
 troscope. In this way, with a quartz plate 45 mm. thick, the line 4809 of 
 the zinc arc in quartz can be completely removed and the two lines 4721 
 and 4679 transmitted. This method is especially useful in the study of the 
 fluorescence excited in various bodies by monochromatic light. 
 
 If it is necessary to separate radiations of very nearly the same wave- 
 length, for example if we wish to work with the light of one of the two 
 sodium lines, the following arrangement can be used: A quartz plate about 
 2 cm. in thickness, cut parallel to the axis, is mounted between crossed nicols, 
 with its axis making an angle of 45° with the principal planes of the polar- 
 izing prisms. The source is placed behind a vertical slit 2 or 3 mm. in 
 width, and the light, after traversing the polarizing system is brought to a 
 focus by a lens. A number of concentric maxima and minima will be 
 formed, the light of D, and D, being found in adjacent maxima. The 
 wave-length which is not desired can be stopped by a screen of suitable 
 dimensions placed at the focus of the lens. In this way it is possible to 
 obtain a source of Dior Deradiation of sufficient intensity to show distinct 
 fringes ina Michelson interferometer. By acurious coincidence this method 
 occurred independently to the writer and to Professor Michelson on the same 
 day. It has been found to give excellent satisfaction. The thickness of 
 the quartz plates used in either of the above cases depends upon the close- 
 ness of the lines which it is desired to separate. 
 
 Weare under great obligation to the Actiengesellschaft fiir Anilinfabrika- 
 tion and to Meister, Lucius & Briining, both of which firms presented the 
 Johns Hopkins University with a large collection of aniline dyes. 
 
ATLAS OF ABSORPTION SPECTRA. 
 
 OBJECT OF THE PRESENT INVESTIGATION. 
 
 If we look over the literature of the subject of absorption of light we 
 fail to find a collection of absorption spectra presented in such a manner as 
 to enable the observer to select at a glance a substance which produces 
 either general or selective absorption in any specified part of the visible or 
 ultra-violet spectrum. The wave-lengths of the absorption bands and other 
 characteristics of the absorption exhibited by innumerable natural and arti- 
 ficial compounds and mixtures, both inorganic and organic, may be found 
 in a great many books, journals, memoirs, and dissertations. If all of these 
 results were reproduced and catalogued in one volume they would not satis- 
 factorily fulfil the requirements just mentioned, because the different experi- 
 menters have had various objects in view and hence they have worked in 
 various and limited parts of the spectrum, have used different numerical 
 dispersions, have employed optical systems of unlike dispersion curves, have 
 not made it possible even to reduce their results to graphical form much less 
 to a common basis of wave-lengths and normal dispersion, etc. The nearest 
 approach to a work of the kind under consideration is made by the publica- 
 tions of J. Formanek, especially the two volumes entitled respectively ‘‘ Die 
 Qualitative Spektralanalyse anorganischer Kérper” and ‘‘Spektralanaly- 
 tischer Nachweis kiinstlicher organischer Farbstoffe;” Berlin, 1900,  For- 
 manek’s investigations are very extensive and complete from the point of 
 view explicitly stated in the preface to the last-named volume. It was his 
 aim to develop a practical spectroscopic method of procedure by which any 
 given organic coloring matter could be unambiguously identified. He says: 
 
 ‘‘Das Princip des hier beschreibenen neuen Verfahrens beruht auf der Kombina- 
 tion der spektralanalytischen Beobachtung und der chemischen Untersuchung ; dieses 
 Verfahren liefert nicht nur sichere Resultate, sondern sein Vortheil liegt auch darin, 
 dass man mit Hilfe desselben alle einzelnen Farbstoffe von einander unterscheiden 
 kann.’’ 
 
 Formanek, in order to obtain his results, varied the concentrations of 
 his solutions until each absorption band of a given substance became in suc- 
 cession as well defined as possible, so that the wave-lengths of their maxima 
 might be read off with precision. This method is preéminently adapted to 
 locating maxima, but it gives very little, if any, information relative to the 
 
 absorption between and beyond the maxima, for bodies exhibiting marked 
 : 3 
 
4 ATLAS OF ABSORPTION SPECTRA. 
 
 selective absorption, and it tells even less about substances presenting 
 weak, general absorption. Another important respect in which Formanek’s 
 diagrams fail to give the data required by the first sentence of this section is 
 that he confined his measurements to eye observations, unaided by phos- 
 phorescent screens, and hence he omitted the entire ultra-violet region. 
 In fact, his wave-lengths have the limits 420~2 and 741Iyp, 1. e., from 
 “above” the G line to a little ‘‘ below” the aline. Formanek used a prism 
 spectroscope to the dispersion of which he gives no clue. 
 
 To fill in this gap in the then existing collections of absorption spectra 
 the present research was begun in the spring of 1903. Its chief object is Zo 
 furnish graphical representations, on a normal scale of wave-lengths, of the 
 absorption spectra, both in the visible and in the ultra-violet regions, of a reason- 
 ably large number of compounds. 
 
 The most obvious use to which such a collection can be put is the pro- 
 duction of color screens either for photographic work or for removing higher 
 orders of spectra from the first order, in the case of diffraction gratings. It 
 also makes possible the selection of such solutions as will transmit relatively 
 narrow, and hence roughly monochromatic, regions of the spectrum. Such 
 solutions are often convenient substitutes for somewhat elaborate pieces of 
 apparatus which first disperse the light by a prism (or grating) and then 
 permit any desired portion of the resulting spectrum alone to continue unin- 
 terrupted by means of a suitable slit and screens. Other directions in which 
 the data given below may be of practical value need not be pointed out here. 
 
 SELECTION OF MATERIAL, APPARATUS, ETC. 
 
 That a great deal of time was consumed in constructing apparatus and 
 in performing preliminary experiments is shown by the fact that, although 
 the investigation was entered upon in the spring of 1903, it was not until 
 July, 1904, that the first really satisfactory negative was obtained. Only 
 aqueous solutions of the aniline dyes have been investigated up to the present 
 time. As is well known, the position of an absorption band may be shifted 
 within wide limits by varying the solvent ;* moreover, many aniline dyes 
 are insoluble, or nearly so, in water. On this account it would have been 
 desirable to have made use of the alcohols, benzol, and other organic com- 
 pounds as solvents for the media under investigation. But difficulties were 
 met with which were not overcome until the study of the dyes was completed. 
 Chief among them may be mentioned the rapid evaporation of the fluid held 
 between the quartz plates. Attempts were made to obviate the difficulty by 
 painting the edges of the wedge with melted paraffin, but the heat of the 
 spark was sufficient to drive off the greater part of the fluid before the 
 
 * See Nos. 158 and 165. 
 
SELECTION OF MATERIAL, APPARATUS, ETC. 5 
 
 exposure was finished. Water is, however, the solvent generally used, and 
 the easiest one to manage. It is moreover free from ultra-violet absorp- 
 tion, which is not true of the majority of the other solvents available, and 
 all dyes which can be dissolved in water can be used for staining gelatin 
 films. The gelatin can be dissolved in the solution of the dye and clean 
 glass plates flowed with the warm solution, or an unexposed photographic 
 plate, after preliminary treatment with thiosulphate of soda and thorough 
 washing, may be stained with the solution of the dye. It is probable that 
 the position of the absorption bands is the same in gelatin as in water, for 
 the indices of refractién of the two media are very nearly the same. 
 
 ABSORBING MEDIA. 
 
 Because of their great variety, strong selective absorption, and general 
 interest, aniline dyes and their related organic compounds were selected as 
 best suited for the study contemplated. 
 
 DISPERSING SYSTEM. 
 
 In order to obtain reasonably normal spectra a spherical, concave, 
 speculum grating, whose radius of curvature was 98.3 cm., was used. For 
 the first order spectra and for short photographic exposures the astigmatism 
 of the reflector did not produce deleterious effects. This-was determined 
 by actual measurements. The length of one line of the ruling was 1.96 cm., 
 and the assemblage of lines covered 5.36 cm. The spectroscopic resolving 
 power was 21,250 (2.125 inches with 10,000 lines per inch). The incon- 
 venience of superposed higher orders will be mentioned later on. To obtain 
 a general idea of the normality of the spectrograms and of the linear dis- . 
 persion it may be stated that, by calculation one millimeter the center of 
 which was at 214.7», Or 399.4uu, OF 656.34, covered 25.77, 25.84, and 
 25.71 A. U., respectively, for the spectrum was designed to be normal at 
 the air line 399. 4p. 
 
 PHOTOGRAPHIC MATERIAL. 
 
 Because of the short radius of curvature of the focal surface (about 49 
 cm.) celluloid films were employed in most cases. The films used through- 
 out were M. A. Seed’s ‘‘L-ortho cut negative films,” size 5 by 7 inches. 
 The emulsion is by no means equally sensitive over the field of wave-lengths 
 studied, i. e., from 0.21 to 0.634. The chief maximum of sensitiveness is 
 in the yellow, about 0.56. A much weaker maximum is near o.49. The 
 middle of the less sensitive intervening region is very roughly 0.52». 
 
 For the short exposures given throughout, these films are not appreciably 
 influenced by wave-lengths longer than about 0.614. The resultant effect of 
 the Nernst glower and the Seed emulsion is best understood by referring to 
 fig. 102, plate 26, for which the times of exposure were, in order, 2 seconds, 
 5 seconds, 15 seconds, 30 seconds, 1 minute, 2 minutes, and 3 minutes. 
 
6 ATLAS OF ABSORPTION SPECTRA. 
 
 Various schemes to make the resultant action more uniform were tried 
 and other makes of films were tested, but no improvement on the simple 
 combination of the Seed emulsion and the Nernst glower resulted, therefore 
 they were used almost exclusively. The Seed films are good in the ultra- 
 violet as is shown by the fact that with an exposure of 5 minutes the alumin- 
 ium line at 185 was clearly recorded. To see if appreciable shifts in the - 
 apparent positions of the absorption bands were produced by the yellow 
 maximum and the green minimum of the Seed films, negatives of the same 
 absorbing medium, under exactly the same conditions, were taken on sev- 
 eral different makes of films and plates which did not exhibit maxima and 
 minima of sensitiveness for the same wave-lengths. Also, other and inde- 
 pendent tests of this possible source of error were made. The conclusion 
 was that no noticeable displacements of the bands were caused. However, 
 in the cases of brown and other visibly colored solutions, exhibiting weak, 
 general absorption, the observer of the appended positives must be careful to 
 distinguish between true absorption and the spurious effects in the vicinity 
 of O. 52H. 
 
 In photographing bands in the orange and red, Cramer ‘‘Trichromatic ” 
 plates were found to be the best and hence they were used. The plates 
 being plane they had to occupy a mean position with respect to the focal 
 surface of the grating. Since only a comparatively small region of wave- 
 lengths was thus recorded, no measurable errors were introduced. In fact, 
 in the region considered, the second order ultra-violet of a discontinuous 
 spectrum taken on a film and on a plate could be superposed line for line. 
 
 ' The developer used was a simple hydrochinone solution made up 
 according to Jewell’s formula.* 
 
 SOURCES OF LIGHT. 
 
 ’ 
 
 For wave-lengths from ‘‘above” 0.65” to ‘“‘below’’ 0.326, and for 
 exposures of about one minute, the Nernst glower was found to be the most 
 satisfactory. Prevailing circumstances made desirable the use of 104 volt 
 glowers on a circuit carrying about 133cycles. The emissivity of the Nernst 
 lamp varies so very greatly with the e. m. f. impressed upon its terminals 
 that it was obligatory to keep in series with the glower a Thomson A.C. 
 ammeter having a range from zero to two amperes and graduated directly 
 to 0.02 ampere. Fluctuations of more than 0.02 ampere invariably resulted 
 in a ‘spoiled photograph, consequently boxes containing variable metallic 
 resistance were maintained in series with the ammeter and thus, in spite of 
 large changes in the load on the dynamo, due to other experimental circuits, 
 it was possible to prevent the effective current in the filament from changing 
 
 
 
 *L. E. Jewell. Astrophys. Jour., v. XI, 1900, pp. 240-243. 
 
SELECTION OF MATERIAL, APPARATUS, ETC. 7 
 
 by more than o.o1 ampere. The current was usually o.8 ampere or a little 
 less. The ammeter was appreciably more sensitive to small changes in the 
 terminal voltage than a comparably graduated Thomson A. C. voltmeter, 
 because the current shunted through the voltmeter was not negligible in 
 comparison with the current which fed the glower. Among other sources the 
 electric arc was given a fair trial and discarded for two reasons, first, because 
 of the intensity of the carbon and cyanogen bands, and second, because of 
 the inconveniences resulting from its unsteadiness and great emission of heat. 
 
 For wave-lengths between the strong ultra-violet of the Nernst glower 
 and o. 2 a spark discharge in air of about 1 cm. length wasused. In obtain- 
 ing the greater number of the negatives one electrode was composed of an 
 alloy of equal parts by weight of cadmium and zinc and the other was made 
 of sheet brass. The alloy wore away so rapidly that the brass electrode was 
 employed to reduce the labor attendant upon sharpening the terminals. 
 The electrodes were given a form apparently not 
 described before. As is very well known, many 
 spectral lines, both weak and strong, produced 
 by sparks between metallic surfaces extend only 
 a short distance beyond the metal and hence do 
 not offer a continuous source of light| across the 
 entire spark gap. In order to obtain a back- 
 ground of uniform intensity from edge to edge 
 of the negatives it was necessary to use some 
 scheme to nullify the effects of the non-uniformity of emission in the spark. 
 One way of accomplishing this is to rapidly translate the electrodes (main- 
 tained at a fixed distance apart) back and forth parallel to the length of 
 the slit of the spectrograph by some mechanical device. 
 
 The reciprocating action associated with this plan shakes the camera 
 and grating to such an extent as to demand greater rigidity in the apparatus 
 than it usually has. Therefore the electrodes were made in the shape of 
 wedges or chisels with the sharp edges parallel to the slit. The well-known 
 distribution of a rapidly alternating current in a conductor necessitated 
 curving the edges of the electrodes, as is shown in fig. 1, which is 5 natural 
 size. Due to the tearing away of the metal, and to various other causes, 
 the innumerable thread-like sparks changed the positions of their ends so 
 rapidly that the integrating action of the photographic film recorded a 
 perfectly uniform negative for exposures of 15 seconds or more. The 
 exposures generally lasted 75 seconds. The electrodes had to be kept sharp 
 and smooth, for, when this was neglected, the elementary sparks persisted 
 much longer in one position than in another and consequently caused streaks 
 of varying intensity to run along the negatives parallel to their length, as 
 can be seen in some of the positives reproduced in the appended plates, e.g., 
 
 fig. 99, plate 25. 
 
 Sparks 
 
 
 
 Fig. 1.—Flat and edge views. 
 
8 ATLAS OF ABSORPTION SPECTRA. 
 
 The current for the spark was obtained in the following manner: An 
 alternating e. m. f. of about 106 volts (133 cycles) was impressed on the 
 terminals of an induction coil of unknown ratio of turns. Eight or nine 
 amperes commonly flowed in the primary. The interrupter of the coil was 
 thrown out of circuit and the coil therefore performed the functions of a 
 transformer. In parallel with the secondary was placed a Leyden jar about 
 18 inches high and of unmeasured capacity. No auxiliary spark was intro- 
 duced. The system could spark about 2.5 cm. in air between metallic 
 points. 
 
 The great intensity of some of the ies characteristic of all the common 
 metals tried (Al, Cd, Cu, Fe, Pb, Zn, etc.) made these metals undesirable 
 for the present work. Cadmium and zinc were selected only because of the 
 strong continuous background to which they give rise. Uranium, its salts or 
 its earths were not used in this work because they are unmanageable. 
 Naturally the pure metal in air burns to oxide at once; pitchblende can not 
 be worked into a suitable shape (at least, for such specimens as we have 
 been able to obtain); and, pitchblende is so very heterogeneous that the 
 position of the spark can not be depended upon for an instant. To have 
 employed a neutral atmosphere in conjunction with a reciprocating mechanism 
 would have consumed, obviously, too much time and would have demanded 
 too complicated, cumbersome and inconvenient an assemblage of apparatus. 
 
 THE CELL. 
 
 In order to show the variations in the absorption spectrum of a given 
 substance when the thickness of the absorbing layer changed linearly, a 
 wedge-shaped cell was constructed. Vessels made on this principle have 
 been designed and used often before, notably by Angstrom, Gladstone, Govi, 
 Gibbs, Tumlirz, Hodgkinson, F. Melde, Hartley, and others.* Neverthe- 
 less, because the precise form of the cell is supposedly new and certainly 
 useful it may not be superfluous to enter into a detailed description of it 
 here. This little piece of apparatus was designed so that the relative posi- 
 tions of the quartz surfaces through which the light entered into, and emerged 
 from, the absorbing liquid could be varied at will, within certain limits. In 
 other words, matters were so arranged that the liquid could be in the form 
 either of a wedge, of variable angle, with zero thickness at the refracting 
 edge, or of a prism of variable angle and finite depth throughout, or of a 
 plane-parallel layer of changeable thickness. To satisfy these conditions it 
 was convenient to rely upon gravitation to preserve certain parts of the cell 
 in mutual contact. This in turn necessitated both the horizontal position of 
 
 
 
 * See H. Kayser, ‘‘ Handbuch der Spectroscopie,’’ v. 1, pp. 58, 59- 
 
SELECTION OF MATERIAL, APPARATUS, ETC. 9 
 
 the bottom of the cell and (because it was desirable to reduce the number of 
 reflecting surfaces to a minimum) a vertical type of spectrograph. 
 
 The cell comprised five separable parts, as follows: (1) A brass frame- 
 work upon which the other parts rested; (2) a transparent tray, without a 
 lid, which confined the liquid in proper bounds; (3) a transparent boxlike 
 system which gave the upper surface of the liquid the desired position; (4)a 
 vulcanite framework to hold the last mentioned box in place; and (5s) four 
 mahogany pins or pegs to fasten the box to its framework. 
 
 (1) A side view of this framework is presented in figure 2. There 
 were three micrometer screws, all of the same pitch, viz: 1 turn = g in. 
 
 Tr + =0.053'cm. Lhe heads 
 : rit of the screws were grad- 
 e uated, on their upper sur- 
 
 
 
 
 Fig. 2.—Four-fifths natural size. hee screw TI was in the 
 medial plane of the cell while the remaining screws (T’ only is shown) were at 
 the other end of the system, were equidistant from this plane, and were as far 
 apart as possible. The micrometer screws called for vertical scales on the 
 adjacent brass-work to count whole turns. The handle is denoted by HH. 
 A black fiducial mark, F, on a white ground, enabled the experimenter to 
 tell what position the cell occupied with reference to the length of the slit of 
 the spectrograph. The lower end of F moved over a scale parallel to the 
 slit and in the plane of the jaws of the latter. The flange at the bottom of 
 the framework was made of brass only 0.014 cm. thick so that the absorb- 
 ing medium might be as near the slit as possible. 
 
 (2) An accurately ground, plane-parallel plate of quartz 40 mm. long, 
 18.5 mm. wide, and 2 mm. thick had cemented to its periphery four 
 rectangular sheets of thin glass 8 mm. high. Hence, the greatest depth of 
 liquid which could be studied by the aid of this cell was 6 mm. 
 
 (3) In figure 3, a, 4, c, and d designate the vertices 5 
 of the section of a quartz plate, made by a plane per- 
 pendicular to the plane the trace of which is the line  \ b 
 ad. ab was 2 mm., ad was 34.8 mm., and the angle _ Fig. 3.—Four-fifths nat. size. 
 between the planes of ad and dc was 55 minutes of arc. The horizontal 
 width of the wedge was 10 mm. _ Glass walls surrounded three sides of the 
 wedge, as the outline indicates. The reason for using the quartz wedge was 
 to counteract the deviation and dispersion produced by the solution in the 
 cell. The angle of the liquid wedge could be varied until the deviation 
 effected by the quartz wedge nullified the average action of the absorbing 
 solution. At first it was supposed that with liquid wedges of 15 or so 
 minutes of arc a plane-parallel quartz plate could be used successfully instead 
 
 
 
10 ATLAS OF ABSORPTION SPECTRA. 
 
 of the quartz wedge. This was true for some dyes but for concentrated 
 solutions of certain other dyes (notably the sodium salt of p-methoxy- 
 toluene-azo- #-naphthol-di-sulphonic acid) some compensating system was 
 absolutely necessary. Finally, the quartz wedge was made with the utmost 
 care by an expert optician, special pains being taken to have the edge 
 through d, perpendicular to the plane aécd, as sharply defined as possible, 
 and the surfaces whose traces are denoted by ad and dc were accurately 
 plane. 
 
 (4) Figure 4 presents a side view and an end view of the vulcanite frame 
 into which the quasi-box just described fitted. This frame was shaped 
 
 —— , out of a single block of vulcanite, for 
 experience showed that a cemented 
 system of several pieces was not dur- 
 
 able; also a dielectric was needed to 
 keep the sparks from jumping to the 
 screws. P indicates a little depression 
 
 Fig. 4.—Four-fifths natural size. which fitted over the point of the 
 screw T. P’ designates the end of a straight line along which the rounded 
 extremity of the screw T’ slid. P” is the cross-section of a shallow, 
 V-shaped groove along which the pointed end of the third screw, T”, like- 
 wise slid. The perforations M, M’, etc., correspond to each other and to 
 the associated wooden pegs mentioned above as (5). 
 
 Figure 5 is an unconventional 
 sketch of the cell when completely 
 assembled. 
 
 A cell of the construction just 
 
 Fig. 5. described is very well suited to the 
 study of thin layers of solutions in solvents of relatively high boiling-points, 
 such as water and amy] alcohol, but, unless inclosed in some suitable vessel, 
 it is not applicable to solvents of lower boiling-points like ethyl alcohol, 
 ether, chloroform, etc. 
 
 
 
 
 
 
 
 CEMENTS. 
 
 A few words concerning cements may not be superfluous because a great 
 many receipts were tried and none was considered entirely satisfactory. 
 No single cement was found which satisfied the following three necessary 
 conditions : (a) Of being unaffected by hot or cold water ; (4) of being insolu- 
 ble in the alcohols, ether, chloroform, carbon bisulphide, etc. ; (c) of drying 
 or setting in three or four days, at most. 
 
 The plan used by Prof. H. N. Morse, in waterproofing cells for the 
 study of osmotic pressure, gave the best results and hence it was followed 
 
SELECTION OF MATERIAL, APPARATUS, ETC. II 
 
 in fastening together the quartz and glass parts of the cell described in the 
 last section. These parts were first fastened together with Khotinsky 
 cement in the usual way, that is, by heating them in an air bath, to any 
 convenient temperature above the melting point of this cement, and by 
 heating a stick of the adhesive mixture in a Bunsen flame and then applying 
 it to the surfaces of the hot quartz and glass. 
 
 Since this resinous cement is soluble in ethyl and amy] alcohol and other 
 solvents, and because it is attacked by various liquids, such as an aqueous 
 solution of potassium permanganate, it was necessary to coat the exposed sur- 
 faces of the cement with something which was chemically inert towards the 
 solutions to be studied. Such a substance is a solution of rubber in carbon 
 bisulphide. This solution was made and used as follows: From an adequate 
 length of black, soft, rubber connecting-tubing segments about 2 cm. long 
 were cut and heated in an evaporating dish over a Bunsen flame until the 
 sections fused, ran together, and formed a very sticky, viscous liquid. (A 
 single long piece of tubing does not liquefy at all satisfactorily.) The liquid 
 state persisted after the contents of the evaporating dish had been allowed 
 to cool down to about room temperature. Carbon bisulphide was next 
 poured into the dish and the contents of the latter were stirred until a 
 homogeneous solution resulted. 
 
 The relative proportions of the carbon bisulphide and rubber used were 
 immaterial and were determined by convenience only The solution can be 
 retained indefinitely in a tightly stoppered bottle and used whenever needed. 
 A thin layer of the solution was painted over the Khotinsky cement, after 
 which the quartz-glass system was heated in an air bath at about 100° C. 
 until the layer became dry and hard, and was no longer sticky. (Of course, 
 during the first part of the process the transparent elements of the cell had 
 to fit over a suitable wooden ‘‘form,”’ because Khotinsky cement softens too 
 much at 100° C. to maintain objects in their proper relative positions.) After 
 this another thin coat of the rubber. solution was applied and the heating 
 continued. This succession of operations was repeated until a thick, hard, 
 dark-brown covering for the joints was obtained. It then made little differ- 
 ence whether the original cement were present or not, as the hard rubber 
 held the quartz and glass together very satisfactorily. 
 
 A cement which dissolves readily in water and in acetic acid but which 
 is not affected by ethyl alcohol, amyl alcohol, carbon bisulphide, glycerin, 
 chloroform, ether, benzol, nitrobenzol, aniline oil B, benzaldehyde, toluol, 
 etc., is made by dissolving 2 pounds of pure gelatin in one quart of water and 
 adding to the resulting solution 7 ounces of nitric acid (sp. gr. 1.35 to 1.42). 
 The final solution is colorless and when applied in thin layers dries in a day 
 or so. It is called Dumoulin’s liquid glue. This glue does not keep well, 
 
iL ATLAS OF ABSORPTION SPECTRA. 
 
 even in a tightly stoppered bottle, and is best made up fresh just before 
 being applied as an adhesive. 
 
 Since the completion of the experimental work on the aniline dyes a 
 cell, in the construction of which no cement at all was employed, has been 
 designed and successfully used by one of us.* This cell could retain any 
 liquids which would not attack glass and quartz and, although it was 
 designed to confine the solutions in plane-parallel layers, nevertheless, the 
 principles involved in its construction were such as to admit of extension to 
 the production of a cell which would be wedge-shaped in the interior and 
 would, at the same time, hold organic solvents, prevent evaporation, etc. 
 
 THE SPECTROGRAPH. 
 
 The essential parts of a vertical section of the spectrograph are outlined 
 in figure 6. They may be tersely described, with the aid of symbols, 
 as follows: In the first place, the elements of the system were adjustable 
 in every respect. Light from the Nernst filament, N, was focused by the 
 concave speculum mirror, R, on the slit, S, whence it continued to the 
 erating, G, from which a portion of it was dispersed in the direction of the 
 sensitized film, F. The distances from the middle of the slit to the centers 
 of the mirror and grating were respectively about 89.5 cm. and 97.1 cm. 
 The electrodes, E, were usually at the distance of 4.2 cm. above the slit and 
 they did not interfere with the passage of the light from the reflector to the 
 slit. No lenses or other reflectors were used. The micrometer head at M 
 indicated the separation of the slit-jaws. © and Q’ denote a screen system 
 such that when QO was vertical the passage of light from the grating to the 
 camera was not interfered with, whereas when Q was horizontal only ultra- 
 violet light of shorter wave-length than 0.4» could reach the photographic 
 film. PP is a horizontal platform with a scale along its front edge. By 
 sliding projecting, horizontal, opaque screens of various widths along this 
 platform it was possible to cut out completely any region or regions of wave- 
 lengths desired. 
 
 In making certain tests, the platform and sliding screens were very 
 convenient. L is the section of a thin, black, metal shutter capable of 
 motion in a horizontal direction and hence at right angles to the length of 
 the photographic films; in other words, parallel to the slit and to the rulings 
 of the grating. A number of long, rectangular slots or openings, suitably 
 spaced and_proportioned, were present in this screen so that strips of differ- 
 ent widths of the films or plates could be exposed to the light from the 
 grating without causing any displacement of the sensitized surfaces with refer- 
 
 
 
 
 
 *The description of the details of the cell is given on pages 241 to 243 of Publication No. 60 of the 
 Carnegie Institution of Washington, entitled: Hydrates in Aqueous Solution. By Harry C. Jones. 
 
THE SPECTROGRAPH. 13 
 
 ence to the grating and slit. This was necessary for impressing comparison 
 spectra, etc. H and H’ suggest the rack-and-pinion system by the aid of 
 which the films could have unexposed portions brought successively opposite 
 to some selected opening in the slide-screen L. D and D’ denote two of 
 the four doors which gave access to 
 the interior of the spectrograph, and 
 which made it possible to close up 
 the camera light-tight, while making 
 various adjustments with the rest of the 
 system. The camera was made so 
 that, when it contained neither a film 
 nor a plate, it was possible for the 
 experimenter to look directly at the 
 erating and to make observations with 
 the assistance of an eye-piece. 
 
 Certain black-on-white scales and 
 ruby-glass windows (Z, for example) 
 enabled the experimenter to know the 
 
 precise relative positions of the various 
 " accessories on the interior of the spec- 
 trograph, when the entire system was 
 shut up and exposures were being made. 
 Numerous dull black diaphragms and 
 screens (Aj, Ay, As, As As, etc.) pro- 
 tected the photographic film from the 
 unusable light which came from the cen- 
 tral image, I, and from all the spectra 
 except the one desired. Uj, and O; 
 give the extreme rays of so much of the 
 first order spectrum as was studied, 
 that is, U; and O, correspond respec- 
 tively to about 0.20 and 0.6254. Ob- 
 viously, the spectrograph was dull black, 
 both inside and out, and contained 
 plaited black velvet in appropriate 
 places. A general idea of the size of 
 the apparatus may be derived from 
 the following dimensions: From RK to 
 the plane of BC — 198.5 cm.; BC 
 — 34.5 cm.; the bottom edge perpen- 
 dicular to BC — 27.5 cm.; BJ = 116 
 Fig. 6.—One-tenth natural size. cm. a and JK — 29 cm. 
 
 
 
 
 
 
 
 
 
I4 ATLAS OF ABSORPTION SPECTRA. 
 
 MANNER OF EXPERIMENTING. 
 SOLUTIONS. 
 
 A small, known mass of a selected dye was carefully weighed on a 
 chemical balance, and put at the bottom of a medium-sized test-tube. 
 Then distilled water was run from a burette into the test-tube, and the 
 latter shaken up from time to time, until the resulting solution appeared to 
 have the proper concentration. As would be expected, practice produced 
 skill in judging absorption of visible light, but to get the right concentration 
 with respect to ultra-violet light was not always soeasy. The greatest error 
 in measuring the solvents was about 0.2 per cent. Since the concentrations 
 are only intended to serve as general guides to an understanding of the 
 spectrograms, a higher degree of accuracy would have been superfluous. 
 Neither was there any reason, in general, for noting the volume of solution 
 which contained a known number of grams of pure solvend; in other words, 
 changes in volume due to the processes of solution were not regarded. 
 
 ADJUSTMENT OF THE CELL. 
 
 Especial care was taken to remove all coloring matter from the cell 
 before introducing another solution into it. Dust caused more trouble than 
 anything else. After cleaning the quartz and glass elements of the cell the 
 various parts of the latter were assembled and, when a frzsm of liquid was 
 to be studied, the micrometer screws regulated in the following manner: 
 All the screws were turned down so as not to touch the vulcanite framework, 
 and:thus to cause the quartz wedge to rest on the quartz plate. Then the 
 screw I had its point elevated again and again until it just touched the 
 deepest part of the depression P. (See figures 2, 3, 4, and 5.) This 
 condition was attained by gently rocking the system around the edge d of 
 the quartz wedge, somewhat after the fashion of experimenting with certain 
 types of spherometer. Thus the zero position of the cell was determined, 
 before each experiment, of course. Next, guided by the circular and plane 
 scales, the observer turned up the screw T until the desired angle, between 
 the wedge and plate, was known to obtain. After this, the screw corre- 
 sponding to T’ was turned up until its tip projected far enough into the groove 
 P” to prevent the quartz wedge and its accessories from sliding over the 
 quartz plate around the point T as pivot, but yet not far enough to raise the 
 vulcanite frame the least bit. Finally, a small amount of the solution was 
 poured into the cell and the latter was then placed on the very thin brass 
 sheet which rested upon and protected the jaws of the slit. 
 
 As soon as the cell was placed over the slit and the glower had been 
 lighted the cell was moved forward and backward, parallel to the slit, while 
 one edge of the field of view was examined with an eye-piece, until a position 
 of the cell was obtained for which the light passing through the quartz wedge 
 
MANNER OF EXPERIMENTING. 15 
 
 at its refracting edge (d of figure 3) illuminated the very limit of the 
 field of view as seen through the chosen slot of the shutter (L of figure 6). 
 The position of the mark on the handle of the cell (F of figure 2), with 
 respect to the horizontal scale in the plane of the slit-jaws, was then read off. 
 If the cell were then moved, ever so little, in one direction the width of the 
 brightly illuminated field could be seen to be less than the opening in the 
 shutter; whereas, if the cell were translated in the opposite sense no increase 
 in the width of the illuminated field occurred. At this opportunity, eye- 
 observations of the absorption between 0.400» and 0.625 were always 
 made and the facts recorded. 
 
 When the concentration of the liquid in the cell was much too great or 
 far too small this instrument had to be cleansed and filled with a solution of 
 more suitable absorbing power, obviously, but when the concentration was 
 not too remote from the best value the effective depth of the cell was varied 
 until the desired result was obtained. 
 
 All three screws were raised and regulated in an obvious manner when 
 prisms of liquid having nowhere infinitesimal thickness were wanted. When 
 layers of liquid of uniform depth were studied a system much like that 
 shown in figure 3, but which had for bottom a plane-parallel plate of 
 quartz 2 mm. thick, was substituted for the quartz-wedge system. 
 
 CALIBRATION OF THE CELL. 
 
 The diedral angles formed by the cell were calculated from the dimen- 
 sions of the instrument, and also from measurements made with a spec- - 
 trometer. 
 
 EXPOSURES AND SPECTROGRAMS. 
 
 The majority of the spectrograms consist of three distinct photographs 
 taken side by side and as close together as possible. (,See the plates.) The 
 width of each photograph was practically the same as the width of the 
 opening in the shutter L. Numerous trials showed that this field of view 
 was completely filled with light, with no overlapping on the grating-side of 
 the opaque portions of the shutter, when the length of the slit was dia- 
 phragmed down to 10.5mm. Consequently, the slit was limited to a length 
 of a very little more than this number and the cell was moved along exactly 
 10.5 mm. between the taking of two adjacent photographic strips on the 
 same film. By this means, the thickness of absorbing liquid through which 
 the light passed to the very edge of one photographic strip was equal to the 
 thickness subsequently traversed by the light which recorded itself at the 
 contiguous edge of the adjacent strip. Of course, the best appearing records 
 were obtained when the film holder, actuated by the rack-and-pinion system, 
 was moved, by an amount exactly equal to the width of the opening in the 
 shutter. A casual inspection of the positives reproduced in the appended 
 
16 ATLAS OF ABSORPTION SPECTRA. 
 
 plates shows that mechanical shifts, in wave-lengths, of the strips on one 
 complete spectrogram, with reference to one another, exist. This may mar 
 the appearance of the photographs somewhat, but the ultra-violet spark lines 
 show the magnitude of the displacements so that corrections can be made, 
 and hence the ultimate scientific value of the results is not decreased. 
 
 The order of events in taking a complete negative of ¢hree strips was 
 invariably as follows: The thickest layer of absorbing liquid was over the 
 opening of the slit first, then the intermediate layer, and last of all, the 
 thinnest layer, which usually tapered to infinitesimal depth. This sequence 
 enabled the comparison spectrum to be taken by moving the shutter, L, 
 without jarring the film-holder, so as to minimize the shift of this spectrum 
 relative to the adjacent photographic strip. For negatives of more than three 
 strips precisely the reverse succession was adopted because it was easier to 
 commence with the cell in adjustment and then to raise the quartz wedge 
 parallel to itself than to lower all three micrometer screws by the same 
 number of turns until the quartz wedge just barely came into contact with 
 the quartz bottom of the cell. With the screen Q horizontal the first expo- 
 sure with the spark was taken. The screen was lowered and the second 
 exposure was made, this time with the Nernst glower. These two exposures 
 produced the first of the three photographic strips. Next the film-holder 
 and cell were moved the proper distances, as explained above. The glower 
 and spark exposures followed in the order named. After again moving the 
 film-holder and cell, the fifth and sixth exposures were produced by 
 the spark and glower respectively. Finally the cell and diaphragm were 
 removed from the slit, another opening in the shutter was adjusted before 
 the film, and the comparison spectrum impressed. In general, the glower 
 exposures lasted 60 seconds, the ultra-violet exposures 75 seconds, and the 
 comparison exposures 35 seconds. The width of the slit was always 0.008 
 cm. In any one complete spectrogram the exposures to the Nernst light 
 were all equal to each other and those for the ultra-violet were related to 
 one another in the same manner. Experience showed that the intervals 60 
 and 75 seconds were best suited to cause the overlapping ends of the photo- 
 graphic impressions to blend as if they had been produced simultaneously 
 by light from a single source. With the longest exposures used, the light 
 from the glower did not affect the films and plates for wave-lengths as short 
 as 0.315 and, since the field photographed did not comprise wave-lengths 
 longer than 0.63», there was no trouble produced by the ultra-violet of the 
 second order. The screen Q took care of this matter so far as the spark 
 exposures were concerned. Figures 14 and 15, plate 4, indicate how the 
 processes just explained can be extended to negatives as wide as may be 
 desirable and hence to as deep layers of absorbing liquid as may be wished.* 
 
 *Of course, a cell deeper than 6 mm. would be necessary if the matter were pushed very far. 
 
 
 
RESULTS. 17 
 
 RESULTS. 
 
 INTERPRETATION OF THE CURVES. 
 
 If the distances from the edge of a positive which is adjacent to the 
 comparison spectrum (which edge therefore corresponds to zero depth of 
 liquid in the cell) to arbitrary points on the boundary of a sharply-defined 
 absorption curve be called ordinates, and if wave-lengths be considered as 
 abscisse, we may say that the absorption constants* associated with any 
 two chosen wave-lengths are inversely proportional to the ordinates belong- 
 ing to these wave-lengths. This statement involves certain assumptions, 
 about emission curves and sensibility curves, a discussion of which will not 
 be given here. 
 
 If the edge of an absorption band is a straight line at right angles to the 
 length of the picture it means that the position of this side of the band 
 will not appreciably change with wide variations in the concentration of the 
 solution; in other words, the limit of absorption will remain at the same 
 wave-length regardless of the concentration. This is roughly the case in 
 figs. 4 and 15 of plates 1 and 4 at the respective wave-lengths 0.29» and 
 0.515, and for most of the narrow bands of figs. 96, 100, and ror. If this 
 condition holds for all the bands of a given substance, which are within or 
 near the confines of the visible spectrum, the color of the light transmitted 
 by the solution will be the same no matter how much the concentration be 
 varied. This is well illustrated by solutions of the salts of neodymium and 
 praseodymium. 
 
 When the boundary of an absorption band is a straight line inclined to 
 the axis of wave-lengths it may be inferred that the limit of the band will be 
 displaced in proportion to the change of concentration, and that the factor of 
 proportionality depends upon the angle which the line makes with the axis of 
 abscissae. This is exemplified in fig. 45, plate 12, by the portions of the 
 band, at wave-length 0.47 corresponding to the thicker layers of liquid. 
 
 In like manner, the general relation between the displacements of the 
 limits of absorption and the associated changes in concentration may be 
 easily inferred when the confines of the absorption bands are curved either 
 convex or concave. 
 
 EXPLANATION OF THE TABLES. 
 
 Two plans suggest themselves for the sequence of the experimental data, 
 viz: (a) To classify the material on the basis of the characteristics of the 
 absorption spectra, i. e., the succession, intensity, etc., of the bands and 
 regions of absorption ; (4) to arrange the results according to the chemical 
 
 : —Kl 
 ein fee 
 
18 ATLAS OF ABSORPTION SPECTRA. 
 
 nature of the absorbing media. Because the first method conforms more 
 closely to the professed object of the present research than the second, every 
 scheme consistent with it was tried which suggested itself. The great num- 
 ber of combinations on the negatives of the effects of weak, general absorp- 
 tion with definite, intense bands, combined with more or less uncertainty as 
 to the interpretation of the negatives in the region for which the source of 
 the discontinuous spectrum had to be used, made it impossible to find a 
 satisfactory permutation of the photographic records. Consequently the 
 second plan suggested above was followed as far as the text is concerned. 
 The spectrograms, on the contrary, are arranged, as far as possible, so as 
 not to have widely different absorption spectra succeed one another on the 
 same plate.* The organic coloring matters succeed one another in the same 
 order as is given to them in the English translation by A. G. Green of a 
 book by G. Schultz and P. Julius entitled ‘‘A Systematic Survey of the 
 Organic Colouring Matters’ (Macmillan & Co., London, 1904). This con- 
 nection between the contents of the volume just named and the material 
 recorded below has the advantage of making it easy to find out many things 
 about the dyes which can not be appropriately given here, such as the names 
 of their discoverers, their literature, patents, methods of preparation, their 
 behavior with various reagents, chemical constitution, etc. 
 
 The descriptive tables following this explanatory section present the 
 experimental results in the following order: 
 
 (1) The absorption of a small number of interesting intermediate prod- 
 ucts, so-called, arranged according to the alphabetical order of their names. 
 
 (2) The absorption of such dyes as were studied and were capable of 
 identification with the dyes discussed in the book by Schultz & Julius. 
 
 (3) The absorption of such dyes as were not unquestionably the same 
 as any given in the reference volume. The accounts of these dyes follow 
 the alphabetical order of their commercial names. 
 
 (4) The absorption of certain miscellaneous objects of more or less 
 interest, in alphabetical order. 
 
 Whenever a number without qualification is given to a substance it 
 refers to the present account, but when a number is quoted from the volume 
 by Schultz & Julius attention is called to the fact by the abbreviation S. & J. 
 
 In the brief account of any one dye the details are presented in the 
 sequence explained by the following sentences: 
 
 First. The arbitrary number of the substance in the present list is given. 
 
 Second. The commercial name of each substance is recorded precisely 
 as it was labeled by the firm which furnished the coloring matter. When 
 
 *Plate 2 is an exception to this statement. 
 
RESULTS. 19 
 
 two firms sent the same dye under the same or under different names the 
 circumstance is explicitly presented. 
 
 Third. Immediately after the commercial name that of the factory is 
 given. The dyes were obtained from three sources. Both the Actiengesell- 
 schaft fiir Anilinfabrikation and Meister, Lucius & Briining presented a large 
 number of dyes of their manufacture to the Johns Hopkins University. The 
 other dyes were purchased from the firm of Eimer & Amend, New York. 
 
 The following abbreviations are used throughout. 
 
 [A.] Actiengesellschaft fiir Anilinfabrikation, Berlin (The Berlin Aniline Co.). 
 
 [A.A.C.] The Albany Aniline Color Works, Albany, New York. 
 
 [B.] Badische Anilin-und Sodafabrik, Ludwigshafen am Rhein (The Baden Co.). 
 
 [By.] Farbenfabriken vorm. Fr. Bayer & Co., Elberfeld (The Bayer Co.). 
 
 [C.] Leopold Cassella & Co., Frankfurt am Main. 
 
 [D.] Dahl & Co., Barmen. 
 
 [D. H.] L. Durand, Huguenin & Co., Basle and Hiiningen. 
 
 [G.] J. R. Geigy, Basle. 
 
 [I. ] Société pour |’ Industrie Chimique (formerly Bindschedler & Busch), Basle. 
 
 [K.] Kalle & Co., Biebrich am Rhein. 
 
 [M.] Farbwerke vorm. Meister, Lucius & Briining, Hochst am Main (Meister, 
 
 Lucius & Briining, Limited). 
 [O.] K. Oehler, Offenbach am Main. 
 [P.] Société Anonyme des Matiéres Colorantes de St. Denis, Paris. 
 
 Fourth. The chemical name of the absorbing medium is given. 
 
 Fifth. Reference is made either to the figure (or figures) and plate 
 which belong to the substance under discussion itself or to a figure which is 
 very much like the spectrograms of the dye considered. 
 
 Sixth. When possible, the number of the dye or the page of the inter- 
 mediate product, as found in the volume of Schultz & Julius, is recorded. 
 
 Seventh. The color and superficial character of the dry coloring matter 
 is suggested. 
 
 Eighth. The color of the solution as observed in a test-tube is followed 
 by the color in the cell. The change of color with thickness is often 
 significant. 
 
 Ninth. Then follows the concentration in grams of dry solvend ina 
 liter of solvent. The term ‘‘saturated”’ is to be understood in its general, 
 practical sense and not in the almost unattainable, theoretical sense. 
 Parenthetical, qualifying words, such as ‘‘(heated, filtered),” call attention 
 to the fact that the substance does not dissolve readily in water, or fue the 
 solution contained gritty, foreign material, etc. 
 
 Tenth. Next is given the angle between the quartz plates forming the 
 top and bottom of the various cells used. In the same line the numbers 
 denote in order the minimum and maximum depths of solution through 
 which the light passed before acting upon the outer limits of the negative. 
 The intermediate thicknesses vary linearly, of course. The same angle is not 
 
20 ATLAS OF ABSORPTION SPECTRA. 
 
 always associated with the same maximum depth, even when the minimum 
 thickness is unchanged, because several cells of different dimensions were 
 employed. 
 
 Eleventh. Finally, a brief account of the most noticeable characteristics 
 of the absorption spectrum, between the limits 0.20» and 0.63», is furnished. 
 
 The results of eye-observations of the absorption spectra come first and 
 serve as checks on the photographic records. The data obtained visually 
 are qualitatively reliable for all strong bands between o. 40% and 0.63». For 
 cases of very weak, general absorption much less importance must be 
 ascribed to the visual results because, unfortunately, the cells were not con- 
 structed so as to present side by side, in the field of view, two spectra, the 
 one of the light after passing through the absorbing solution, the other of 
 the unabsorbed light direct from the Nernst glower. 
 
 When the solution is fluorescent, or decomposes when ultra-violet light 
 falls upon it, or possesses a characteristic odor, etc., the facts are noted. 
 That the spectrograms are not distorted by the presence of fluorescent light, 
 but give as true records of the absorption spectra of fluorescent compounds 
 as they do for non-fluorescent solutions, was ascertained by direct experi- 
 ments. (In particular, see the record for solution No. 107.) 
 
 Lastly, the apsroximate wave-lengths of the maxima and minima of 
 absorption, as obtained from the spectrograms, are given, beginning near 
 0.204 and continuing to 0.634. When the wave-lengths of the ‘‘ends”’ of a 
 region of absorption are given they obviously have significance only under 
 the conditions of thickness of absorbing layer, of concentration, of length 
 of photographic exposure, etc., which prevailed at the time when the 
 spectrogram was taken. The maxima are not subject to the same limita- 
 tions. The fact that the Seed films can produce spurious absorption bands 
 in the green must be again emphasized. (See figure 102, plate 26.) 
 
 When the end of the spectrogram, which marks the fading away of the 
 sensitiveness of the emulsion from the yellow to the orange, is practically a 
 straight line perpendicular to the length of the spectrogram it means that 
 there is no appreciable general absorption in this locality, but when the limit 
 just specified is approximately a right line inclined at an obtuse angle to the 
 positive direction of the axis of wave-lengths it signifies that appreciable 
 general absorption is present in this region. 
 
 
 
TABULATED DATA OF ABSORPTION. 
 
 INTERMEDIATE PRODUCTS. 
 
 1. Amidonaphtholdisulphonic Acid H. (M.) 
 Mig.t,-pl..1; pp, 57.and 58, 5. & J. 
 Grayish-white lumps. In _ solution 
 
 brownish yellow, colorless. 
 Saturated. 
 Angle 27.3’. Depth 0 to 0.25 mm. 
 No visible absorption. Intense blue 
 fluorescence. Ultra-violet absorp- 
 tion ends about 0.347p. 
 
 2. B-Naphtholdisulphonic Acid G. (M.) 
 
 Peres ands, pl, 1; p. 51, 0. & J. 
 
 Pinkish-white powder. In_ solution 
 
 colorless. 
 
 Saturated. 
 
 Angle 27.3’. Depth 0 to 0.25 mm. 
 
 No visible absorption. Intense blue 
 
 fluorescence. Absorption ends very 
 definitely and follows approximately 
 a straight line from 0.346p to 0.356p. 
 Fig. 5 shows absorption exhibited by 
 a solution made by diluting a certain 
 volume of the saturated solution to 
 eight times its original value. 
 
 3. p-Nitraniline. (Powder, “extra.”) (M.) 
 
 Page 12, S. & J. 
 
 Lemon-yellow powder. In solution yel- 
 
 low, faint yellow. 
 
 Saturated. 
 
 Angle 37.1’. Depth 0 to 0.34 mm. 
 
 No visible absorption is produced by 
 
 a column 6 cm. deep. Entire ultra- 
 violet absorption is weak. A region 
 of slight absorption from 0.204 to 
 0.255 is followed by transparency 
 as far as 0.34n. Faint absorption 
 extends from 0.34 to 0.40n. From 
 0.40p to 0.634 no absorption is no- 
 ticeable. 
 
 4. o-Nitrobenzaldehyde. (M.) 
 
 Page 61, S. & J. 
 
 White needles. In solution colorless. 
 
 Saturated. 
 
 Angle 31.2’. Depth 0 to 0.29 mm. 
 
 Extremely weak absorption from 0.20p 
 to 0.24u. Transparent from 0.24 to 
 0.63. 
 
 5. p-Nitrosodimethylaniline. 
 
 Piet pl. Bs pgaedak J. 
 
 Dark-green, crystalline powder. In 
 solution brownish yellow, clear yel- 
 low. 
 
 Saturated. 
 
 Angle 23.4’. Depth 0 to 0.21 mm. 
 
 5. p-Nitrosodimethylaniline—Continued. 
 
 Strong absorption in violet and blue 
 increasing towards the ultra-violet. 
 A remarkably transparent region 
 extends from 0.30u to 0.375u. All 
 the strong lines between 0.324 and 
 0.3634 are transmitted with almost 
 no decrease in intensity.* A very 
 round band stretches from 0.375 to 
 0.448 with its maximum at 0.432». 
 Complete transparency from 0.49p 
 to 0.63p. 
 
 6. Resorcine (techn. pure). (M.) 
 
 Pigs 4; pt. 25 Pp. 455.00. Oci); 
 
 White, crystalline lumps. In solution 
 colorless. 
 
 Nearly saturated. 
 
 Angle 29.3’. Depth 0 to 0.27 mm. 
 
 No visible absorption. Very faint yel- 
 low in a layer a decimeter thick. Ab- 
 sorption ends very abruptly and 
 shows an almost vertical right line 
 determined by 0.287 and 0.293». 
 
 CoLorInG MATTERS. 
 
 y/3 ee Yellow. (A.) Naphthol Yellow 
 
 (M.) Sodium salt of dinitro-a- 
 naphthol-8-monosulphonic acid. 
 Bigs. 4, DigliseNO. Asc Oa 
 Orange-yellow powder. In_ solution 
 brownish yellow, pure yellow. 
 Saturated (heated). 
 Angle 31.2’. Depth oto 0.29 mm. 
 Intense band in violet, ultra-violet side 
 invisible. Absorption decreases from 
 0.20n% towards 0.3354. Transparent 
 region around 0.3354. <A pair of 
 overlapping bands extends from 
 about 0.3454 to 0.4654. Their max- 
 imum absorption is at 0.3854 and 
 their least absorption is at 0.4Ip. 
 Very transparent from 0.465, to be- 
 yond 0.63y. 
 
 8. Aurantia. Ammonium salt of hexanitro- 
 
 diphenylamine. 
 
 Fie. 309 pL. 720s NO: Dao. en]: 
 
 Reddish-brown crystals. In solution 
 dull red, yellow. 
 
 10 g. per liter (filtered). 
 
 Angle 42.5’. Depth o to 0.36 mm. 
 
 General absorption in violet. Absorp- 
 tion decreases from 0.20% towards 
 0.28u. Transparent region from 
 0.284 to 0.33u. Wide band from 
 0.33u to 0.49% with its maximum 
 
 *R.W. Wood. ‘On Screens Transparent only to Ultra-Violet Light and their use in Spectrum Photography.” 
 
 Phil. Mag., v. 5, Feb., 1903, pp. 257-263. 
 
 2I 
 
 
 
PSP 
 
 ATLAS OF ABSORPTION SPECTRA. 
 
 8. Aurantia—Continued. 
 
 at o.41u. As the concentration in- 
 creases the absorption encroaches 
 much faster on the transparent re- 
 gion in the ultra-violet than on the 
 limit in the yellow. Very trans- 
 parent to yellow and orange. 
 
 9. Fast Yellow. (B.) Sodium salt of 
 
 amidoazotoluene-disulphonic acid. 
 
 Somewhat similar to fig. 40, pl. 10; 
 NG.0, >. & J- 
 
 Brownish-yellow powder. In solution 
 brownish yellow, yellow. 
 
 15 g. per liter. 
 
 Angle 23.4’. Depth o to 0.21 mm. 
 
 Absorption in violet and blue. The 
 region of partial transmission in 
 the ultra-violet is not as complete 
 for solution No. 9 as for solution 
 No. 32. Also the boundaries of the 
 violet band are somewhat more defi- 
 nite for the former solution than 
 for the latter. The less refrangible 
 side of this band is more like the 
 corresponding region for solution 
 No. 129, fig. 13, pl. 3. Absorption 
 decreases gradually from 0.20” to 
 semi-transparency at about 0.34». A 
 wide, diffuse band extends from this 
 region to about 0.4754. Its maxi- 
 mum is at 0.40n. Transparent from 
 
 0.475p to 0.63p. 
 
 10. Orange G. (A.) Sodium salt of benzene- 
 
 azo-B-naphthol-disulphonic acid G. 
 Fig. 30, pl. 8; No. 14, S. & J. 
 Yellowish-red powder. In solution 
 
 red, yellow. 
 
 Saturated (heated). 
 Angle 21.3’. Depth 0 to 0.18 mm. 
 Strong absorption in blue and green. 
 
 Sharp on yellow edge. Two ultra- 
 
 violet bands meet at about 0.29pm in 
 
 a semi-transparent spot. The maxi- 
 
 mum of the less refrangible band is 
 
 0.325u. This strong band meets a 
 
 very weak one at 0.3654. The center 
 
 of the weak band is 0.39n. The 
 weak band joins an intense one at 
 
 0.424. This last band joins a still 
 
 stronger band, from which it is not 
 
 resolved, at 0.4854. The maximum 
 of the stronger band is at 0.505p. 
 
 Absorption ceases at 0.534. Com- 
 
 plete transparency to 0.63. — 
 
 11. Ponceau 2 G. (M.) Sodium salt of 
 
 benzene -azo-8-naphthol - disulphonic 
 acid R. 
 
 Ir. Ponceau 2 G—Continued. 
 
 Fig. 6, pl. 2; No. 15, S. & J. 
 
 Bright-red powder. In solution yel- 
 lowish red, yellow. 
 
 7 g. per liter (filtered). 
 
 Angle 27.3’. Depth o to 0.25 mm. 
 
 Comparatively weak band in the blue- 
 green, with a shadowy, fainter com- 
 panion on the yellow side. Absorp- 
 tion decreases gradually from 0.20p 
 to 0.34. The nearly transparent 
 region from 0.34 to 0.44» is inter- 
 rupted by a very faint band having 
 its maximum at 0.394. The pair of 
 stronger bands extends from 0.44» 
 to 0.545u. Transparent from 0.545m 
 to 0.63u. Same empirical formula 
 as No. 10. No. Io is derived from 
 the G acid, while No. 11 is a salt 
 of the R acid. 
 
 12. Chrysoidine. Hydrochloride of diami- 
 
 doazobenzene. 
 
 Fig. 7; pl. 2. NO. 17; os 
 
 Reddish-brown powder. In solution 
 brown, yellow. 
 
 Io g. per liter (filtered). 
 
 Angle 23.4’. Depth 0 to 0.21 mm. 
 
 Absorption in violet, blue, and green 
 with maximum in the indigo. Ab- 
 sorption decreases from 0.20 to 
 0.334. Transparent from 0.33a to 
 0.36n. A pair of broad, unseparated 
 bands absorbs from 0.36 to 0.54. 
 The band of greater refrangibility 
 is the more intense and has its max- 
 imum at 0.434. Transparent from 
 0.54 to 0.63. The less refrangible 
 band disappears first on dilution. A 
 five-strip negative shows that the 
 outer boundaries of the pair of bands 
 are steep and definite. 
 
 13. Chromotrope 6 B. (M.) Sodium salt 
 
 of p-acetamidobenzene-azo-1 :8-dioxy- 
 naphthalene disulphonic acid. 
 
 Fig)’8, pl. 2;"No*38, S. aus 
 
 Grayish-brown powder. In solution 
 red, pink. 
 
 5-71 g. per liter. 
 
 Angle 11.7’. Depth 0 to 0.11 mm. 
 
 Strong absorption in green-yellow. 
 Transparent from 0.354 to 0.465p. 
 A strong band has its beginning at 
 0.4654 and its maximum at 0.515p. 
 The less refrangible side joins a weak 
 companion band extending into the 
 
 orange and red. More dilute solu- 
 
 tions show that the intense band is 
 symmetrical with respect to its max- 
 
 oe =, o 
 
 
 
COLORING MATTERS. 23 
 
 13. Chromotrope 6 B—Continued. 
 
 imum until it joins the associated 
 band. More concentrated solutions 
 show very distinctly the weaker 
 band in the orange-red. 
 
 14. Azo Coccine 2 R. (A.) Sodium salt 
 
 of xylene-azo-a-naphthol-p-sulphonic 
 acid. 
 
 Fig. 9, pl. 2; No. 50, S. & J. 
 
 Reddish-brown powder. In solution 
 salmon pink, salmon pink. 
 
 Saturated (heated). 
 
 Angle 27.3’. Depth 0 to 0.25 mm. 
 
 Narrow band in the blue-green. An 
 absorption band of very indefinite 
 edges extends from about 0.48» to 
 0.53H with its maximum at 0.505p. 
 Transparent from 0.53p to 0.63p. 
 
 15. Brilliant Orange G. (M.) Sodium salt 
 
 of xylene-azo-8-naphthol-mono - sul- 
 phonic acid. 
 
 Fig. 31, pl. 8; No. 54, S. & J. 
 
 Cinnabar-red powder. In _ solution 
 yellowish red, deep yellow. 
 
 7 2. per liter. 
 
 Angle 23.4’. Depth 0 to 0.21 mm. 
 
 Intense absorption in blue-green and 
 blue. Very sharp on the yellow side. 
 Absorption decreases from 0.20p to 
 weak absorption at 0.295u, then in- 
 creases to maximum absorption at 
 0.32n. At 0.355 semi-transparency 
 obtains. A definite band has its 
 maximum at 0.3954 and joins the 
 next band at 0.434. The next band 
 has its maximum at 0.48» and joins 
 the adjacent band at o.505u. The 
 final band has a maximum at 0.52u. 
 Absorption ends at 0.545%. Com- 
 plete transparency to 0.63n. The 
 band at 0.395 disappears rapidly 
 with dilution. Same empirical 
 formula as solution No. 14. 
 
 16. Ponceau 2 R. (A.), (M.) Sodium salt 
 
 of xylene-azo-B-naphthol-disulphonic 
 acid. 
 
 Similar to fig 55, pl. 14; No. 55, S. & J. 
 
 Brownish-red powder. In solution red, 
 pink. 
 
 5 g. per liter (heated). 
 
 Angle 27.3’. Depth 0 to 0.25 mm. 
 
 Hazy-edged band in the blue-green. 
 Similar absorption to that of solu- 
 tion No. 17 in the ultra-violet and 
 identical with it in the visible region. 
 
 17. Ponceau 3 R. (A.), (M.) Sodium salt 
 
 of y-cumene-azo - B - naphthol-disul- 
 phonic acid. 
 
 17. Ponceau 3 R—Continued. 
 
 Fig. 55, pl. 14; No. 56, S. & J. 
 Dark-red powder. In solution red, pink. 
 5 g. per liter (heated). 
 
 Angle 29.3’. Depth 0 to 0.27 mm. 
 
 An absorption band is in the blue- 
 green. It has its maximum at 0.50p 
 and extends from about 0.474 to 
 0.544. Transparent from 0.54» to 
 
 0.63. 
 18. Crystal Ponceau 6 R. (A.), (M.) 
 
 Sodium salt of a-naphthalene-azo- 
 B-naphthol-disulphonic acid. 
 
 Similar to fig. 55, pl. 14; No. 64, S. & J. 
 
 Brownish-red crystals with golden re- 
 flex. In solution light red, pink. 
 
 5 g. per liter (heated). 
 
 Angle 27.3’. Depth 0 to 0.25 mm. 
 
 Hazy-edged band in the blue-green and 
 green. Similar absorption to that of 
 solution No. 17. The ultra-violet ab- 
 sorption, however, is somewhat more 
 intense and extends to greater wave- 
 lengths for solution No. 18 than for 
 solution No. 17. The visible band 
 extends from 0.465 to 0.56% with 
 its maximum at 0.5Ip. 
 
 19. Bordeaux B. (M.) Sodium salt of a- 
 
 naphthalene-azo - B - naphthol -disul- 
 phonic acid. 
 
 Similar to fig. 19, pl. 5; No. 65, S. & J. 
 
 Brown powder. In solution red, red. 
 
 4.18 g. per liter. 
 
 Angle 42.5’. Depth o to 0.36 mm. 
 
 Hazy-edged band in the green. The 
 sides of the band in the green and 
 the orange end of the spectrogram 
 slope a little more for solution No. 
 19 than for No. 106. Band from 
 0.485" to 0.5454, with maximum at 
 0.515u. The least refrangible ends 
 for all the spectrograms slope, thus 
 showing that there is some general 
 absorption in the orange. More con- 
 centrated solutions show that the 
 greatest transparency occurs. at 
 0.414. Same empirical formula as 
 No. 18. 
 
 20. Coccinine B. (M.) Sodium salt of p- 
 
 methoxy.-toluene - azo - 8 - naphthol- 
 disulphonic acid. 
 
 Similar to fig. 55, pl. 14; No. 73, S. & J. 
 
 Dark-red powder. In solution bright- 
 red, red. 
 
 13.64 g. per liter. 
 
 Angle 12.8’. Depth 0 to 0.11 mm. 
 
 Strong absorption in green-yellow. 
 Similar to solution No. 17, save that 
 
 
 
 eae 
 
 pe 
 
24 
 
 ATLAS OF ABSORPTION SPECTRA. 
 
 20. Coccinine B—Continued. 
 
 a weak absorption band seems to 
 have the limits 0.315 and 0.355n, 
 with a maximum at 0.33. Intense 
 band from 0.465 to 0.555, with a 
 maximum at o.510u. Transparent 
 from 0.555 to 0.63u. Very concen- 
 trated solutions or deeper layers 
 show that the transparent region on 
 both sides of 0.414 becomes opaque 
 much faster than the orange and red 
 region. Red is transmitted when all 
 shorter wave-lengths are absorbed 
 completely. The solution exhibits 
 strong dispersive power. 
 
 21. Eosamine B. (A.) Sodium salt of p- 
 
 cresol - methyl-ether-azo-a-naphthol- 
 disulphonic acid. 
 
 Fig. 52, pl. 13; No. 74, S. & J. 
 
 Reddish-brown powder. In solution 
 yellowish red, pink. 
 
 8.89 g. per liter. 
 
 Angle 21.3’. Depth o to 0.18 mm. 
 
 Strong band in blue-green and green. 
 Intense, round band from 0.465p to 
 0.565, with its maximum at about 
 0.52u. Transparent from 0.565 to 
 0.63u. Same empirical formula as 
 No. 20. 
 
 22. Erika B. (A.) Sodium salt of methyl- 
 
 benzeny] - amido - thio-xylenol-azo-a- 
 naphthol-disulphonic acid. 
 
 Fig. 57, pl. 15; No. 78, S. & J. 
 
 Reddish-brown powder. In solution 
 red, pink. 
 
 6.67 g. per liter. 
 
 Angle 19.5’. Depth 0 to 0.18 mm. 
 
 Strong absorption in blue, green, and 
 green-yellow. Two unresolved bands 
 absorb strongly from 0.46 to 0.59p. 
 The more refrangible band shows 
 greater intensity than its companion 
 and has its maximum at 0.52y. Slight 
 absorption in the orange is followed 
 by greater transparency in the red. 
 
 23. Emin Red. (A.) Sodium salt of methyl- 
 
 benzenyl - amido - thioxylenol-azo-B- 
 naphthol-sulphonic acid. 
 
 Fig. 29, pl. 8; No. 80, S. & J. 
 
 Red powder. In solution red, pink. 
 
 Saturated (heated). 
 
 Angle 31.2’. Depth o to 0.29 mm. 
 
 Weak, hazy absorption in blue and 
 green. Strong absorption from 0.20p 
 to about 0.35u, then a rather rapid 
 decrease in absorption sets in. From 
 
 23. Emin Red—Continued. 
 
 0.38 to 0.454 a semi-transparent re- 
 gion exists. A round band extends 
 from 0.45p to 0.54u. Its maximum 
 is near 0.495n. The less refrangible 
 side of this band is far more definite 
 than its ultra-violet edge. Trans- 
 parent from 0.54p to 0.63y. 
 
 24. Janus Green. (M.) Chloride of safra- 
 
 nine-azo-dimethylaniline. 
 
 No. S175. & J: 
 
 Olive-green, crystalline powder. In so- 
 lution blue, blue. 
 
 4.6 g. per liter. 
 
 Angle 17.0’. Depth 0 to 0.14 mm. 
 
 Band in orange and orange-red. Trans- 
 parent to pure red. Very general ab- 
 sorption in ultra-violet, decreasing 
 gradually from 0.20p to 0.40p. Trans- 
 parent from 0.40n to 0.5154. The 
 absorption band begins at 0.515p. 
 
 25. Tropeoline O. (C.) Sodium salt of p- 
 
 sulphobenzene-azo-resorcinol. 
 
 Similar to fig. 37, pl. 10; No. 84, S. & J. 
 
 Brown powder. In solution wine-color, 
 yellow. 
 
 Saturated (heated). 
 
 Angle 25.5’. Depth 0 to 0.21 mm. 
 
 Faint absorption in the violet. Similar 
 absorption to that of solution No. 81. 
 Weak absorption from 0.20% to 
 0.275. Transparent from 0.275, to 
 0.325u. A weak, hazy band extends 
 from 0.325 to 0.4In with its maxi- 
 mum around 0.374. Transparent 
 from 0.4Ip to 0.63. 
 
 26. Tropeoline OOO No. 1. Sodium salt of 
 
 p-sulphobenzene-azo-a-naphthol. 
 
 Similar to fig. 31, pl. 8; No. 85, S. & J. 
 
 Reddish-brown powder. In solution 
 red, salmon pink. 
 
 6.67 g. per liter. 
 
 Angle 21.3’. Depth 0 to 0.18 mm. 
 
 Absorption in violet, blue, and green. 
 Similar absorption to that of solu- 
 tion No. 15. Rather strong absorp- 
 tion continues from 0.20n to about 
 0.33H and then decreases rapidly to 
 semi-transparency. A tolerably trans- 
 parent region is from 0.35p to 0.37. 
 Three unresolved bands with maxima 
 at about 0.41p, 0.48u, and 0.52 fol- 
 low. The intermediate points of less 
 intensity of absorption are 0.435u 
 and 0.450n. At 0.545 the absorption 
 ceases. Transparent from 0.545h to 
 0.63). 
 
COLORING MATTERS. 25 
 
 27. Tropzoline OOO No. 2. Sodium salt of 
 
 p-sulphobenzene-azo-8-naphthol. 
 
 No. 86, S. & J. 
 
 Bright, orange powder. In solution 
 deep red, salmon pink. 
 
 14 g. per liter. 
 
 Angle 21.31 Depth o to 0.18 mm. 
 
 Visible absorption and spectrogram 
 identical with No. 26. Similar ab- 
 sorption to that of solution No. 15. 
 Nos. 26 and 27 have the same em- 
 pirical formule, but differ by a and B 
 in the naphthol. 
 
 28. Methyl Orange III. (P.) Sodium salt 
 
 of p-sulphobenzene-azo - dimethylani- 
 line. 
 
 iar, pl 11; No. 87,5. & J. 
 
 Ocher-yellow powder. In solution red, 
 yellow. 
 
 Saturated (heated). 
 
 Angle 27.3’. Depth 0 to 0.25 mm. 
 
 Absorption in blue and green. A strong 
 band extends from 0.36 to 0.525p. 
 This band is very round with its 
 maximum at 0.44». Transparent 
 from 0.5254 to 0.63. 
 
 29. Tropxoline OO. (C.) Sodium salt of 
 
 p-sulphobenzene-azo - diphenylamine. 
 Similar to fig. 40, pl. 10; No. 88, S. & J. 
 Yellow powder. In solution yellowish 
 red, yellow. 
 6 g. per liter (heated and filtered). 
 Angle 25.5’. Depth 0 to 0.21 mm. 
 Delicate absorption in violet and blue. 
 Similar absorption to that of solu- 
 tion No. 32. The extreme ultra- 
 violet absorption is weak because the 
 lines near 0.23» show on all three 
 photographic strips. From 0.385 to 
 0.47p a weak absorption band obtains 
 with its maximum at 0.43. The 
 substance is very transparent to yel- 
 low and red. Nos. 29 and 32 have 
 the same empirical formule. No. 29 
 is the para-compound and No. 32 is 
 the meta-. No. 29 shows weaker 
 absorption than No. 32. 
 
 30. Curcumeine. (A.) Mixture of nitrated 
 
 diphenylamine yellow with nitrodi- 
 phenylamine. 
 
 Fig: 22; plh.33.No..91, Sak. J. 
 
 Ocher-yellow powder. In solution red, 
 yellow. 
 
 Saturated (heated). 
 
 Angle 27.3’. Depth 0 to 0.25 mm. 
 
 30. Curcumeine—Continued. 
 
 Absorption in violet, blue, and blue- 
 green. Absorption complete at 0.20p, 
 decreasing very gradually with com- 
 paratively definite contour to 0.455. 
 Transparent from 0.455p to 0.63p. 
 
 31. Azo Acid Yellow. (A.) Azo Yellow, 
 
 concentrated. (M.) Mixture of 
 nitrated diphenylamine yellow with 
 nitro-diphenylamine. 
 
 Similar to fig. 12, pl. 3; No. 92, S.& J. 
 
 Ocher-yellow powder. In _ solution 
 brownish yellow, yellow. 
 
 Saturated (heated). 
 
 Angle 27.3’. Depth 0 to 0.25 mm. 
 
 Strong absorption of violet, blue, and 
 blue-green. Similar absorption to 
 that of solution No. 30. Absorption 
 is nearly complete and uniform from 
 0.20p to about 0.394. Then the ab- 
 sorption decreases in a gently slop- 
 ing curve to about 0.505. Trans- 
 parent to yellow and red. Nos. 30 
 and 31 are mixtures of the same con- 
 stituents and have very similar re- 
 gions of absorption. 
 
 32. Metanil Yellow. (A.) Sodium salt of 
 
 m-sulphobenzene-azo-diphenylamine. 
 
 Fig. 40, pl. 10; No. 95, S. & J. 
 
 Brownish-yellow powder. In solution 
 yellowish red, yellow. 
 
 4.29 g. per liter (filtered). 
 
 Angle 23.4’. Depth 0 to 0.21 mm. 
 
 Absorption in violet and blue. A band 
 with very indefinite boundary ex- 
 tends from about 0.36u to 0.47. The 
 maximum is near 0.4In. Transparent 
 to yellow and red. A very concen- 
 trated solution shows complete ab- 
 sorption from 0.20 to 0.5Ip with a 
 semi-transparent spot at 0.34» and 
 maximum absorption at 0.40". Ab- 
 sorption ceases abruptly at 0.535m. 
 
 33. Naphthylamine Brown. Sodium salt of 
 
 p-sulphonaphthalene-azo-a-naphthol. 
 Similar to fig. 11, pl. 3; No. 101, S. & J. 
 Brown powder. In solution reddish 
 brown, almost colorless. 
 II.11 g. per liter (heated and filtered). 
 Angle 30.0’. Depth o to 0.45 mm. 
 Very weak, general, indefinite absorp- 
 tion for all visible colors of shorter 
 wave-lengths than the yellow. Sim- 
 ilar absorption to that of solution 
 No. 47. Absorption was nearly com- 
 plete from 0.20n to 0.274». From 
 
34. Fast Red A. (A.) 
 
 ATLAS OF ABSORPTION SPECTRA. 
 
 33. Naphthylamine Brown—Continued. 
 
 the latter wave-length the absorption 
 decreased very gradually to a maxi- 
 mum of semi-transparency at about 
 0.43u. The apparent absorption at 
 0.52u is much exaggerated by the 
 lack of relative sensitiveness of the 
 photographic film at this spot. Very 
 slight absorption from 0.55 to 0.63p. 
 
 A weaker solution presented only 
 
 ultra-violet absorption. 
 
 New Coccine O. 
 (M.) Sodium salt of p-sulphonaph- 
 thalene-azo-B-naphthol. 
 
 Figs27 ipl, 9; Nonroz, Suk J: 
 
 Brownish-red powder. In solution red, 
 pink. 
 
 5 g. per liter (heated). 
 
 Angle 27.3’. Depth 0 to 0.25 mm. 
 
 Hazy absorption in blue-green and 
 general absorption in blue. Muddy- 
 looking solution. Two partially re- 
 solved bands extend from 0.415p to 
 0.544 with maxima of absorption at 
 about 0.454% and 0.5054. The less 
 refrangible band is the more intense. 
 Orange and red are transmitted, but 
 the sloping end of the photograph 
 shows that slight, general absorption 
 is present in orange. Nos. 33 and 34 
 have the same empirical formule. 
 They differ by a and B naphthol. 
 
 35. Azo Rubine S. (A.) Sodium salt of 
 
 p-sulphonaphthalene-azo-a-naphthol- 
 p-sulphonic acid. 
 
 Similar to fig. 55, pl. 14; No. 103, 
 ee aa Be 
 
 Brown powder. In solution red, pink. 
 
 10 g. per liter. 
 
 Angle 19.5’. Depth 0 to 0.18 mm. 
 
 Absorption in green. Much like solu- 
 tion No. 17 with slight differences in 
 the ultra-violet. Absorption decreases 
 from 0.20p to 0.27p. The strong lines 
 at 0.255 and 0.275» are transmitted 
 by the deepest layer. Absorption in- 
 creases from 0.274 to a maximum at 
 0.3154. Then the absorption de- 
 creases to approximate transparency 
 at 0.36u. Transparent from 0.36 to 
 0.465u. Strong band from 0.465» to 
 0.5554 with maximum at 0.5Ip. The 
 visible band is in the same place as 
 the like band of No. 20, but the 
 ultra-violet is different. Transparent 
 to orange and red. 
 
 36. Fast Red, extra. (A.) Sodium salt of 
 
 p-sulphonaphthalene-azo-f-naphthol- 
 monosulphonic acid. 
 
 Similar to fig. 55, pl. 14; No. 105, 
 Ss. & 
 
 Reddish-brown powder. In solution 
 red, pink. 
 
 7 &. per liter. 
 
 Angle 27.3’. Depth 0 to 0.25 mm. 
 
 Absorption in blue-green and green. 
 Absorption the same throughout as 
 for No. 35 except the position of 
 the visible band. No. 36 absorbs 
 from 0.460p to 0.545 with the max- 
 imum at 0.505. Same empirical 
 formula as for No. 35. 
 
 37. New Coccine. (A.) Sodium salt of 
 
 p-sulphonaphthalene-azo-8-naphthol- 
 disulphonic acid. 
 
 Similar to fig. 52, pl. 13; No. 106, 
 bette: 
 
 Scarlet-red powder. In solution yel- 
 lowish red, pink. 
 
 10 g. per liter. 
 
 Angle 23.4’. Depth 0 to 0.21 mm. 
 
 Absorption in blue-green and green. 
 Similar absorption to that of solu- 
 tion No. 21. The ultra-violet absorp- 
 tion of solution No. 37 seems to con- 
 sist only of one band whereas that 
 of solution No. 21 seems to be separ- 
 ated into two bands by a minimum of 
 absorption near 0.274. Absorption 
 decreases from 0.20» to transparency 
 about 0.37n. A strong, round band 
 from 0.445 to 0.56% has its maxi- 
 mum at o.5Ip. Transparent from 
 0.56pn to 0.63p. 
 
 38. Fast Brown 3 B. (A.) Sodium salt of 
 
 sulphonaphthalene-azo-a-naphthol. 
 Similar to fig. 23, pl.6; No. 111, S. & J. 
 Dark-brown, glistening powder. In so- 
 lution reddish brown, faint brown. 
 15 g. per liter. 
 Angle 27.3’. Depth 0 to 0.25 mm. 
 Absorption most intense in blue-green 
 and green with slight general absorp- 
 tion on both sides. Similar absorp- 
 tion to that of solution No. 60. A 
 fairly strong band from 0.46pm to 
 0.54» has its maximum at 0.51p. No 
 definite band from 0.54 to 0.63p, but 
 general absorption is made evident 
 by the slope of the end of the nega- 
 tive. 
 
COLORING MATTERS. oF 
 
 39. Mordant Yellow O. (M.) Sodium salt of 
 
 sulphonaphthalene-azo-salicylic acid. 
 
 Similar to fig. 13, pl. 3; No. 116, S. & J. 
 
 Yellow powder. In solution reddish 
 yellow, yellow. 
 
 10 g. per liter. 
 
 Angle 31.2’. Depth 0 to 0.29 mm. 
 
 Absorption in the violet only. Similar 
 absorption to that of solution No. 
 129. Strong absorption from 0.20p 
 to 0.284. Slight weakening of ab- 
 sorption from 0.28n to 0.34. Ab- 
 sorption attains a maximum at 0.36n 
 and then slopes gradually, with a 
 comparatively definite edge, to trans- 
 parency at 0.44n. From this point 
 to 0.634 complete transparency ex- 
 ists. 
 
 bo WianiieVeliow R- (M.) 
 
 Similar to fig. 37, pl. 10; No. 124, 
 Ss. & 
 
 Orange-yellow powder. In _ solution 
 clear yellow, yellow. 
 
 Saturated. 
 
 Angle 31.2’. Depth 0 to 0.29 mm. 
 
 Faint absorptiag, in violet.’ Similar ab- 
 sorption to that of solution No. 81. 
 Absorption is comparatively strong 
 at 0.20% and decreases to partial 
 transparency near 0.295u. A toler- 
 ably weak band extends from this 
 region to about 0.435u. Its maximum 
 is indeterminate. Transparent from 
 
 0.44p to 0.63p. 
 
 41. Resorcine Brown. (A.) Sodium salt of 
 
 xylene - azo - resorcin-azo-benzene-p- 
 sulphonic acid. 
 
 Fig. 38, pl. 10; No. 137, S. & J. 
 
 Brown powder. In solution brown, 
 yellow. 
 
 7.78 g. per liter. 
 
 Angle 23.4’. Depth 0 to 0.21 mm. 
 
 Strong absorption in the violet and 
 blue. A more concentrated solution 
 exhibited absorption in the green 
 and yellow. A long band or region 
 of absorption extends from 0.35 to 
 0.52u. The maximum is near 0.395. 
 There is a slight minimum of absorp- 
 tion at 0.48u. The presence of a 
 weaker, less refrangible band, in- 
 creasing in intensity at 0.48u, is more 
 marked as the concentration is in- 
 creased. More concentrated solutions 
 show that the transparency in the 
 ultra-violet rapidly disappears, 
 
 41. Resorcine Brown—Continued. 
 
 whereas the bands do not encroach 
 as rapidly on the yellow. Trans- 
 parent from 0.534 to 0.63. The 
 absorption of the concentrated solu- 
 tions is like that of solution No. 77, 
 
 fig. 35. 
 
 42. Acid Brown. (D.) Sodium salt of bi- 
 
 sulphobenzene-disazo-a-naphthol. 
 Similar to fig. 39, pl. 10; No. 138, 
 nat af 
 
 Brown powder. In solution brown, 
 yellow. 
 
 7.5 2. per liter. 
 
 Angle 25.5’. Depth 0 to 0.21 mm. 
 
 Absorption in violet and blue. Similar 
 absorption to that of solution No. 8. 
 Very weak absorption from 0.20p 
 to 0.29u. Transparent to continuous 
 background of spark from 0.29» to 
 0.33u. Weak, indefinite absorption 
 band from 0.33n to 0.484, with max- 
 imum indeterminate. Transparent to 
 yellow, orange, and red. 
 
 43. Ponceau B O, extra. (A.) Sodium salt 
 
 of benzene-azo-benzene-azo- B-naph- 
 thol-disulphonic acid. 
 
 Similar to fig. 52, pl. 13; No. 146, 
 Sad, Ji 
 
 Light-brown powder. In solution yel- 
 lowish red, pink. 
 
 71g pershiter: 
 
 Angle 21.5’. Depth 0 to 0.20 mm. 
 
 Strong absorption in blue and green. 
 Similar absorption to that of solu- 
 tion No. 21. Absorption decreases 
 from 0.20n to 0.295u, and then in- 
 creases to a maximum near 0.345. 
 This band fades to semi-transparency 
 about 0.4n. The width and general 
 appearance of the region of separa- 
 tion between the ultra-violet bands 
 and the band in the green resembles 
 much more closely the correspond- 
 ing region for solution No. 48 than 
 for solution No. 21. Transparency 
 continues from 0.4p to 0.44p, where a 
 strong, round band begins. The last 
 band ends at 0.565u. Its maximum is 
 at o.5Ip. Transparent from 0.565p 
 to 0.63u. Absorption from this band 
 moves more rapidly towards the 
 ultra-violet than towards the red, 
 with increasing concentration. Same 
 empirical formula as No. 42. 
 
ATLAS OF ABSORPTION SPECTRA. 
 
 44. Janus Red B. (M.) Chloride of tri- 
 
 methyl-amido - benzene - azo - m - tol- 
 uene-azo-8-naphthol. 
 
 Similar to fig. 23, pl. 6; No. 149, S. & J. 
 Reddish-brown powder. In solution 
 yellowish red, faint yellowish red. 
 
 Saturated. 
 
 Angle 54.6’. Depth 0 to 0.50 mm. 
 
 Pointed, V-shaped, weak band in the 
 blue-green. Similar absorption to 
 that of solution No. 60. Absorption 
 is strong at 0.20u and decreases 
 gradually and in a poorly defined 
 manner to transparency at 0.375p. 
 The transparent region continues to 
 0.455u. An absorption band lies be- 
 tween 0.4554 and 0.540pn, with its 
 maximum at 0.5Ip. Slight general 
 absorption in the yellow and orange, 
 but transparent to the red. 
 
 45.Cloth Red G. (O.) Sodium salt of 
 
 toluene - azo -toluene-azo-8-naphthol- 
 monosulphonic acid. 
 
 Fig. 25, pl..7; No. 153,15..000, 
 
 Reddish-brown powder. In_ solution 
 red, faint pink. 
 
 8.33 g. per liter (heated and filtered). 
 
 Angle 31.2’. Depth 0 to 0.29 mm. 
 
 Bands in blue-green and green with 
 hazy edges and weak general ab- 
 sorption in both directions. A band 
 extends from 0.445 to 0.55u and ap- 
 pears to be composed of a stronger 
 band with a weaker, morerefrangible, 
 unresolved companion. Their maxi- 
 mum of absorption is at 0.515". The 
 slant at the end of the negative shows 
 that weak, general absorption is ex- 
 erted in the orange. Transparent to 
 the red. 
 
 46. Cloth Red O. (M.) Sodium salt of 
 
 toluene - azo-toluene-azo-8-naphthol- 
 disulphonic acid. 
 
 Fig. 21, pl. 6; No. 154, S. & J. 
 
 Dark-brown powder. In solution deep 
 red, very faint red. 
 
 6.36 g. per liter (warmed and filtered). 
 
 Angle 33.2’. Depth 0 to 0.30 mm. 
 
 Maximum of absorption in blue-green 
 with weak absorption in yellow and 
 orange. Absorption band starts at 
 0.485, attains its maximum at 0.52p, 
 and is dissipated in weak general ab- 
 sorption about 0.555. The end of 
 the negative slants appreciably. 
 Transparent to red. 
 
 47. Cloth Red 3 G A. (A.) Sodium salt of 
 
 toluene - azo-toluene-azo-B-naphthyl- 
 amine-monosulphonic acid. 
 
 Fig. 11, pls 7 No. 165), 6): 
 
 Brownish-red powder. In solution red- 
 dish brown, light brown. 
 
 Saturated (heated). 
 
 Angle 1° 57’. Depth 0 to 1.07 mm. 
 
 General absorption in violet, also a 
 maximum of absorption in the blue- 
 green and green. Absorption is about 
 complete at 0.20u and increases very 
 gradually, with hazy contour, to 
 semi-transparency at about 0.42p. 
 Semi-transparency from 0.42m to 
 0.49u. Weak band from 0.49p to 
 0.54». Transparent from 0.54" to 
 
 0.63p. 
 
 48. Ponceau 4 R B. (A.) Sodium salt of 
 
 sulphobenzene - azo - benzene - azo-B- 
 naphthol-monosulphonic acid. 
 
 Fig. 51, pl. 13; No. 160, S. & J. 
 
 Reddish-brown powder. In solution 
 yellowish red, pink. 
 
 10 g. per liter (heated). _ 
 
 Angle 19.5’. Depth 0 to 0.18 mm. 
 
 Strong absorption in blue-green and 
 green. At 0.455 the strong band be- 
 gins and extends to 0.565u, with its 
 maximum about 0.5Ip. Transparent 
 from 0.565 to 0.63p. 
 
 49. Biebrich Scarlet. (K.) Sodium salt of 
 
 sulphobenzene - azo - sulphobenzene - 
 azo-B-naphthol. 
 
 Similar to fig. 51, pl. 13; No. 163, 
 Secu: 
 
 Reddish-brown powder. In solution 
 red, pink. 
 
 6 g. per liter. 
 
 Angle 19.5’. Depth o to 0.18 mm. 
 
 Absorption band in blue-green and 
 green. Absorption decreases from 
 0.20p to about 0.324, where a semi- 
 transparent region appears. This is 
 followed by an absorption band with 
 its maximum at 0.3554. Slight ab- 
 sorption from 0.39p to 0.454. A defi- 
 nite band starts at 0.45u, reaches a 
 maximum near 0.5Ip, and ends at 
 0.5554. Transparent from 0.555» to 
 0.63u. A solution of 10 g. per liter 
 showed almost complete absorption 
 from 0.20p to 0.36u. From 0.395 to 
 0.445m only the first photographic 
 strip received light. The band is very 
 round from 0.4454 to its end at 
 
COLORING 
 
 49. Biebrich Scarlet—Continued. 
 
 0.585u. Transparent to orange and 
 red. Same empirical formula as No. 
 48 and almost identical visible ab- 
 sorption. 
 
 50. Wool Black. (A.) Sodium salt of sul- 
 
 phobenzene-azo - sulphobenzene-azo- 
 p-tolyl-8-naphthylamine. 
 
 Fig.67, plz; No. 166; S..& J. 
 
 Bluish-black powder. In solution pur- 
 ple, light purple. 
 
 5.50 g. per liter (filtered). 
 
 Angle 35.1’. Depth 0 to 0.32 mm. 
 
 Hazy band in yellow spreading indefi- 
 nitely into the orange. Transmits 
 bright red. At 0.49» a region of ab- 
 sorption commences which seems to 
 consist of a hazy central band with 
 a weak, washed-out companion on 
 each side. The chief maximum is 
 about 0.54. Absorption is very weak 
 from 0.60 to 0.63u. A very concen- 
 trated solution shows that the max- 
 imum of transparency is near 0.44. 
 
 51. Ponceau 6 R B. (A.) Sodium salt of 
 
 sulphotoluene - azo - toluene - azo - B- 
 naphthol-a-sulphonic acid. 
 
 Fig. 56, pl. 14; No. 169, S. & J. 
 
 Reddish-brown powder. In solution 
 scarlet red, pink. 
 
 5-38 g. per liter. 
 
 Angle 31.2’. Depth 0 to 0.29 mm. 
 
 Strong band in the green which is 
 more definite on the blue side than 
 on the yellow border. Strong band 
 from 0.465 to 0.5654. The maxi- 
 mum is at 0.514. The band is prob- 
 ably composed of two unresolved 
 bands of which the weaker lies nearer 
 the red. Transparent from 0.565 to 
 0.63p. 
 
 Ie 
 52. Blue-Black. (B.) Sodium salt of sulpho- 
 
 8-naphthalene - azo - a - naphthalene- 
 azo-8-naphthol-disulphonic acid. 
 
 No. 186, S. & J.* 
 
 Bluish-black powder. In solution bluish 
 violet, violet. 
 
 6.69 g. per liter (filtered). 
 
 Angle 33.2’. Depth 0 to 0.30 mm. 
 
 Very indefinite absorption in green- 
 yellow, yellow, and orange, with 
 maximum in yellow. Absorption is 
 strong at 0.20u and decreases gradu- 
 ally to about 0.34n. Approximately 
 transparent from 0.4n to 0.54. Ab- 
 sorption starts near 0.50u, increases 
 to a maximum about 0.54», and de- 
 
 MATTERS. 29 
 
 52. Blue-Black—Continued. 
 
 creases to weak, general absorption 
 from 0.58 to 0.63. 
 
 53. Anthracene Yellow C. (C.) Sodium 
 
 salt of thio-di-benzene-disazo-di-sali- 
 cylic acid. 
 
 Similar to fig. 37, pl. 10; No. 190, 
 Se Ga: 
 
 Brownish-yellow powder. In solution 
 muddy yellowish brown, greenish 
 yellow. 
 
 6 g. per liter (filtered). 
 
 Angle 21.3’. Depth 0 to 0.18 mm. 
 
 Absorption in violet. Somewhat sim- 
 ilar absorption to that of solution 
 No. 81. However, the absorption of 
 solution No. 53 is more intense than 
 that of solution No. 81. Absorption 
 decreases from 0.20p to a semi-trans- 
 parent strip at about 0.2954. Beyond 
 this strip a band with hazy contour 
 extends as far as 0.41» with its max- 
 imum at about 0.34». Transparent 
 from 0.4Ip to 0.63p. 
 
 54. Bismarck Brown. (A.) Hydrochloride 
 
 of benzene-disazo-phenylene-diamine. 
 Fie _7, pl. 2;..NO- 107, sac |. 
 Dark-brown powder. In solution brown, 
 yellow. 
 30 g. per liter (filtered). 
 Angle 19.5’. Depth 0 to 0.18 mm. 
 Visible and photographic absorption 
 identical with that of solution No. 12. 
 
 55.Vesuvine. (B.) Hydrochloride of 
 
 toluene-disazo-m-tolylene-diamine. 
 Fig 7, ploae NOne0l, oe |: 
 Dark-brown powder. In solution red- 
 dish brown, yellow. 
 4.29 g. per liter. 
 Angle 31.2’. Depth 0 to 0.29 mm. 
 Visible and photographic absorption 
 identical with that of solution No. 12. 
 
 56. Congo Orange G. (A.) Sodium salt of 
 
 dipheny] - disazo-phenetol-8-naphthyl- 
 amine-disulphonic acid. 
 
 Fig.33; pl. 93.No: 217, S. & J. 
 
 Brownish-red powder. In solution red- 
 dish yellow, yellow. 
 
 5.36 g. per liter, 
 
 Angle 23.4’. Depth 0 to 0.21 mm. 
 
 Hazy absorption in blue, blue-green, 
 and green with maximum in the 
 green. Tolerably strong absorption 
 decreases from 0.20p to a weak mini- 
 mum near 0.324 and then increases 
 to a maximum about 0.36%. A 
 semi-transparent region lies between 
 
 
 
 
 
 * Spectrogram too indefinite for reproduction. 
 
30 ATLAS OF ABSORPTION SPECTRA. 
 
 56. Congo Orange G—Continued. 59:-Congo Red. (A.) Sodium salt of 
 
 0.405 and 0.44». A weak, hazy band 
 begins at 0.44u and continues to 
 0.475, at which point it joins a 
 more intense band. The latter has 
 its maximum at 0.505 and then de- 
 creases to transparency at 0.53. 
 Transparent from 0.53n to 0.63n. 
 More concentrated solutions empha- 
 size all the maxima of absorption 
 just outlined and the minimum at 
 0.42u. 
 
 57. Chrysamine G. (A.) Sodium salt of 
 
 diphenyl-disazo-bi-salicylic acid. 
 Similar to fig. 36, pl. 9; No. 220, S. & J. 
 Yellowish-brown powder. In solution 
 brownish yellow, faint yellow. 
 7 g. per liter (heated and filtered). 
 Angle 35.1’. Depth 0.26 to 0.58 mm. 
 No visible absorption unless, perhaps, 
 a faint weakening of the extreme 
 violet. Somewhat similar absorption 
 to that of the more dilute solution of 
 No. 77. For the layer used the ab- 
 sorption is nearly complete from 
 0.20u to 0.29. The continuous back- 
 ground is transmitted from 0.29 to 
 0.30n. The limit of the ultra-violet ab- 
 sorption is approximately a straight 
 line joining the wave-lengths 0.365p 
 and 0.395 at the opposite edges of 
 the negative. Transparent from 
 0.395" to 0.63u. More dilute solu- 
 tions and wedges of liquid tapering 
 to infinitesimal thickness show that 
 ultra-violet absorption is very weak. 
 
 58. Cresotine Yellow G. (M.) Sodium salt 
 
 of diphenyl - disazo -bi-o-cresol - car- 
 boxylic acid. 
 
 Similar to fig. 36, pl.g; No. 221, S. & J. 
 
 Yellowish-brown powder. In solution 
 yellow, faint yellow. 
 
 Saturated. 
 
 Angle 39.0’. Depth 0 to 0.36 mm. 
 
 Absorption in violet and indigo. Ab- 
 sorption much like that of the more 
 dilute solution of No. 77. The solu- 
 tion has a peculiar odor. A washed- 
 out band begins at 0.31, passes 
 through a maximum near 0.355p, 
 and then fades away at o.44u. A 
 rather narrow region of semi-trans- 
 parency, the center of which is near 
 0.30, separates this band from a 
 weak, more refrangible ultra-violet 
 band. Transparent from 0.44 to 
 0.63). 
 
 diphenyl-disazo-bi-naphthionic acid. 
 
 Similar to fig. 26, pl. 7; No. 240, S. & J. 
 
 Reddish-brown powder. In solution 
 red, yellowish red. 
 
 5.9 g. per liter. 
 
 Angle 27.3’. Depth 0 to 0.25 mm. 
 
 Absorption in blue, blue-green, and 
 green with maximum nearer the 
 green end. Similar absorption to that 
 of solution No. 69. Absorption de- 
 creases from 0.20u to near 0.284 and 
 then increases to a maximum at 
 about 0.3254. These two partially 
 resolved bands are followed by a re- 
 gion of approximate transparency 
 extending from 0.385, to 0.426 with 
 its maximum at 0.4054. Transpar- 
 ency is terminated at 0.4264 by a 
 pair of wide, hazy bands of which 
 the more refrangible is the weaker. 
 The chief maximum is at 0.505p. 
 Absorption ends at 0.545u. Trans- 
 parent from 0.545 to 0.634. More 
 concentrated solutions show that the 
 ultra-violet and visible bands soon 
 run together, whereas the absorption 
 does not advance much towards the 
 orange. 
 
 60. Congo Corinth G. (A.) Sodium salt 
 
 of diphenyl - disazo - naphthionic-a- 
 naphthol-sulphonic acid. 
 
 Fig. 23, pl. 6; No. 24g" 5sGam 
 
 Greenish-black powder. In solution 
 brownish red, red. 
 
 5.38 g. per liter (heated). 
 
 Angle 27.3’. Depth o to 0.25 mm. 
 
 Absorption in blue-green, green, and 
 yellow. Very general absorption at 
 the red border. Absorption band 
 from 0.46p to 0.555 with its maxi- 
 mum near 0.5154. The end of the 
 negative slants considerably, show- 
 ing that general absorption con- 
 tinues into the orange. Transparent 
 to red. Same empirical formula as 
 No. 61, but different constitution. 
 
 61.Congo Rubine. (A.) Sodium salt of 
 
 diphenyl-disazo-naphthionic acid - B - 
 naphthol-sulphonic acid. 
 
 Similar to fig. 19, pl. 5; No. 243, 
 Ashe 
 
 Greenish, crystalline powder. In solu- 
 tion bluish red, dull red. 
 
 Saturated (warmed). 
 
 Angle 39.0’. Depth 0.26 to 0.62 mm. 
 
COLORING MATTERS. 31 
 
 61. Congo Rubine—Continued. © 
 
 Absorption in blue-green. Absorption, 
 especially in the visible spectrum, 
 similar to that of solution No. 106. 
 A layer about 2 mm. deep absorbs 
 all the visible spectrum except the 
 orange and red. Complete absorp- 
 tion at 0.20 decreases to a minimum 
 near 0.275p, then increases to a maxi- 
 mum at about 0.31, and finally van- 
 ishes in transparency at 0.345. Ab- 
 sorption band from 0.485 to 0.55u 
 with its maximum at 0.52. Trans- 
 parent from 0.554 to 0.63u. Same 
 empirical formula as No. 60, but dif- 
 ferent constitution. 
 
 62. Anthracene Red. (I.) Sodium salt 
 
 of nitrodipheny]l - disazo - salicylic-a- 
 naphthol-sulphonic acid. 
 
 Similar to fig. 56, pl. 14; No. 262, 
 S. & J. 
 
 Brownish-red powder. In solution deep 
 red, pink. 
 
 7.5 ¢. per liter. 
 
 Angle 27.3’. Depth 0 to 0.25 mm. 
 
 Hazy-edged band in the blue-green 
 and green. Similar absorption to 
 that of solution No. 51. Absorption 
 decreases from 0.20n to semi-trans- 
 parency at 0.29. About 0.31 a well- 
 rounded, hazy-edged band _ starts, 
 passes through its maximum near 
 0.364, and ceases at 0.42u. Partial 
 transparency from 0.424 to 0.465p. 
 A symmetrical absorption band pre- 
 vents transmission from 0.465 to 
 0.55¢. Its maximum is near 0.5Ip. 
 Transparent from 0.55u to 0.63pm. 
 Less concentrated solutions show 
 that the ultra-violet absorption is 
 comparatively weak. 
 
 63. Congo Orange R. (A.) Sodium salt of 
 
 ditolyl - disazo - phenetol-8-naphthyl- 
 amine-disulphonic acid. 
 
 Similar to fic. 11, pl. 3; No. 27575. & J. 
 
 Yellowish-red powder. In_ solution 
 brown, yellowish brown. 
 
 5 g. per liter (warmed and filtered). 
 
 Angle 39.0’. Depth 0 to 0.36 mm. 
 
 Indefinite, general absorption in the 
 blue and blue-green. The liquid is 
 not clear, but behaves somewhat like 
 an emulsion. Similar absorption to 
 that of solution No. 47. Absorption 
 decreases from 0.20n to about 0.20p 
 and then remains about constant as 
 far as 0.365. From this point it de- 
 
 63. Congo Orange R—Continued. 
 
 creases to very weak, general ab- 
 sorption at 0.43n. A slight increase 
 in absorption has its maximum at 
 0.515. It is partly, but not entirely, 
 due to the weak spot of the Seed 
 emulsion. Transparent from 0.54 
 to 0.63u. Deeper layers of greater 
 concentration show the minimum of 
 absorption to be the region around 
 
 0.4554. 
 
 64. Benzopurpurine 6 B. (A.) Sodium 
 
 salt of ditolyl - disazo - bi-a-naphthyl- 
 amine-sulphonic acid. 
 
 Similar to fig. 26, pl. 7; No. 278, S. & J. 
 
 Red powder. In solution red, brownish 
 red. 
 
 7.78 2. per liter (filtered). 
 
 Angle 29.3’. Depth 0 to 0.27 mm. 
 
 Hazy-edged band in blue and green. 
 Similar absorption to that of solu- 
 tion No. 69. Strong absorption from 
 0.415 to 0.554. The chief maximum 
 of absorption is at 0.51p. Probably 
 two hazy, unresolved bands, with 
 more refrangible, weaker component. 
 Transparent from 0.55% to 0.63». 
 Weaker solutions show more rapid 
 increase of transparency on the ultra- 
 violet side of the visible band than 
 on the red side. 
 
 65. Benzopurpurine B. (A.) Sodium salt 
 
 of ditolyl-disazo-bi-B-naphthylamine- 
 B-sulphonic acid. 
 
 Similar to fig. 26, pl. 7; No. 279, S. & J. 
 
 Brown powder. In solution reddish 
 brown, brown. 
 
 8.75 ¢. per liter. 
 
 Angle 25.4’. Depth 0 to 0.23 mm. 
 
 Same visible and photographic absorp- 
 tion as No. 69. Identical visible ab- 
 sorption to that of solution No. 64. 
 Solutions Nos. 65 and 69 seem to 
 have only one region of absorption 
 in the ultra-violet, whereas solution 
 No. 64 has a slight minimum of ab- 
 sorption near 0.2754. Nos. 64 and 
 65 have the same empirical formule, 
 but different chemical constitution. 
 
 66. Diamine Red B. (A.) Deltapurpurine 
 
 5 B. (M.) Sodium salt of ditolyl- 
 disazo-bi-B-naphthylamine - sulphonic 
 acid. 
 Similar to fig. 26, pl. 7; No. 280, S. & J. 
 Reddish-brown powder. In solution 
 yellowish red, pink. 
 
ATLAS OF ABSORPTION SPECTRA. 
 
 . 
 
 66. Diamine Red B—Continued. 
 
 6.36 g. per liter (warmed and filtered). 
 
 Angle 25.4’. Depth 0 to 0.23 mm. 
 
 Same visible absorption as No. 64. 
 Similar absorption to that of solution 
 No. 69. Nos. 64 and 66 have the 
 same empirical formule, but differ- 
 ent chemical constitutions. 
 
 67. Brilliant Congo R. (A). Sodium salt 
 
 of ditolyl-disazo - B - naphthylamine- 
 monosulphonic - B-naphthylamine-di- 
 sulphonic acid. 
 
 Similar to fig. 26, pl. 7; No. 281, S. & J. 
 
 Brown powder. In solution, yellowish 
 red, yellowish red. 
 
 8 g. per liter. 
 
 Angle 31.2’. Depth 0 to 0.29 mm. 
 
 Hazy-edged band in blue and green. 
 Similar absorption to that of solution 
 No. 69. A pair of unresolved bands 
 extends from 0.42 to 0.56u, with 
 their chief maximum at 0.5154. The 
 less refrangible band is the more in- 
 tense. Transparent from 0.555 to 
 0.6 p. 
 
 3 
 68. Diamine Red 3 B. (A.) Sodium salt 
 
 of ditolyl-disazo-bi-B-naphthylamine- 
 8-sulphonic acid. 
 Fie "Gi, pl 10 "NG coe, 5. ye 
 Reddish-brown powder. In_ solution 
 reddish brown, brown. 
 7 g. per liter (heated and filtered). 
 Angle 50.7’. Depth 0.64 mm. to 1.10 
 
 mm. 
 
 Hazy-edged absorption in the blue- 
 green and green. A pair of unre- 
 solved bands absorbs from about 
 0.435u to 0.5454. Their maximum 
 is near 0.5154. The more refrangible 
 band is weaker and more indefinite 
 than its companion. Transparent 
 from 0.545p. to 0.63n. 
 
 69. Brilliant Purpurine R. (A.) Sodium 
 
 salt of ditolyl-disazo-naphthionic-f- 
 naphthylamine-disulphonic acid. 
 
 Fig. 26, pl. 7; No. 283, S. & J. 
 
 Red powder. In solution red, pink. 
 
 8.75 g. per liter. 
 
 Angle 25.4’. Depth 0 to 0.23 mm. 
 
 Same visible and photographic absorp- 
 tion as No. 67. Nos. 67 and 69 have 
 the same empirical formule, but dif- 
 ferent chemical constitutions. Ab- 
 sorption gradually decreases from 
 0.204% to partial transparency at 
 0.388u. This minimum of absorption 
 extends to 0.41Ip. A pair of unre- 
 
 69. Brilliant Purpurine R—Continued. 
 
 solved bands absorbs all radiations 
 between 0.411p and 0.563y. The less 
 refrangible band is the more intense 
 and has its maximum at 0.515. 
 Transparent from 0.563p to 0.63. 
 
 70. Rosazurine B. (B.) Sodium salt of 
 
 ditolyl - disazo - bi - ethyl-8-naphthyl- 
 amine-sulphonic acid. 
 
 Similar to fig. 26, pl. 7; No. 285, S. & J. 
 
 Brown powder. In solution red, pink. 
 
 7 2. per liter (heated). 
 
 Angle 27.3’. Depth 0 to 0.25 mm. 
 
 Weak absorption in the green, with 
 very hazy, blue boundary. Similar 
 absorption to that of solution No. 69. 
 The precise size and shape of the 
 visible band matches very closely the 
 corresponding band of solution No. 
 45, fig. 25. Absorption from 0.47p 
 to 0.55, with the maximum near 
 0.5154. Transparent from 0.55u to 
 
 0.03pm. 
 71. Congo Corinth. Sodium salt of ditolyl- 
 
 disazo - naphthionic-a-naphthol-p-sul- 
 phonic acid. 
 
 Similar to fig. 22, pl. 6; No. 286, S. & J. 
 
 Grayish-black powder. In solution red, 
 pink. 
 
 9.09 g. per liter (very gritty; filtered 
 often). 
 
 Angle 21.5’. Depth 0 to 0.20 mm. 
 
 General absorption in green, yellow, 
 and orange. Very weak and hazy 
 towards the red. Similar absorption 
 to that of solution No. 74. Weak, 
 general absorption in ultra-violet, 
 permitting all strong lines to pass 
 through the solution. It fades away 
 about 0.354. Several plates and films 
 show that absorption begins again 
 about 0.494% and becomes relatively 
 small at 0.56u. Weak, general ab- 
 sorption, however, continues to 0.63. 
 The maximum of absorption is inde- 
 terminate. Saturated solutions gave 
 the same general results. 
 
 72. Azo Blue. (By.) Sodium salt of ditolyl- 
 
 disazo-bi-a-naphthol-f-sulphonic acid. 
 
 Somewhat like fig. 22, pl. 6; No. 287, 
 Tans ae 
 
 Bluish-black powder. In solution deep 
 blue, reddish blue. 
 
 4.29 g. per liter. 
 
 Angle 23.4’. Depth 0 to 0.21 mm. 
 
 Hazy-edged absorption in green-yellow, 
 yellow, and orange. The red border 
 
COLORING MATTERS. eK" 
 
 72. Azo Blue—Continued. 
 
 is very indefinite and the maximum 
 appears to be in the yellow. Ab- 
 sorption is like that of solution No. 
 74, except in so far as it is stronger 
 than No. 74 in the orange. Compara- 
 tively weak absorption in the ultra- 
 violet from 0.20u to 0.3554. There 
 are slight indications of two ultra- 
 violet bands with the intervening re- 
 gion near 0.2Qu. Transparent from 
 0.36 to 0.49u. Absorption begins at 
 0.49, increases to 0.53u, then fades 
 to partial transparency near 0.59». 
 Weak absorption from 0.59p to 0.63. 
 
 73. Diamine Black B O. (C.) Sodium salt 
 
 of ethoxy-diphenyl-disazo - bi-amido- 
 naphthol-sulphonic acid. 
 
 Suggested by fig. 22, pl. 6; No. 304, 
 S.& 
 
 Black powder. In solution blue, blue. 
 
 7.5 g. per liter. 
 
 Angle 31.2’. Depth 0 to 0.29 mm. 
 
 Strong absorption in the yellow and 
 orange with diffuse borders. Red is 
 transmitted. The absorption is some- 
 what like that of solution No. 74 
 except in so far as it is stronger than 
 No. 74 in the orange. Absorption 
 decreases from 0.20p to about 0.37p. 
 Transparent from 0.374 to O.5Ip. 
 Absorption extends from 0.5Ip into 
 the clear red. The maximum of ab- 
 sorption is indefinite. 
 
 74.Benzopurpurine 10 B. (A.) Sodium 
 
 salt of dimethoxy-di-phenyl-disazo- 
 bi-naphthionic acid. 
 
 Pee, pl..6; No.307, 5. & J. 
 
 Brownish-red powder. In solution red, 
 pink. 
 
 5-83 g. per liter. 
 
 Angle 23.4’. Depth 0.05 to 0.26 mm. 
 
 Chief absorption in the green. The 
 visible band extends from about 
 0.48 to 0.55 with its maximum at 
 0.515u. The slanting end of the nega- 
 tive denotes general absorption in 
 the orange. 
 
 75. Benzoazurine. Sodium salt of dimeth- 
 
 oxy-diphenyl disazo-bi-a-naphthol - p- 
 sulphonic acid.. 
 
 Somewhat like fig. 22, pl. 6; No. 311, 
 oe. Ss}. 
 
 Bluish-black powder. In solution red- 
 dish blue, blue. 
 
 7.5 g. per liter. 
 
 * Spectrogram too indefinite for reproduction. 
 
 75. Benzoazurine—C ontinued. 
 
 Angle 25.5’. Depth 0 to 0.21 mm. 
 
 No very definite, visible band, but a 
 general weakening of the green, yel- 
 low, orange, and red. The ultra- 
 violet absorption is weak and ends 
 near 0.355. The region of general 
 absorption begins about o.51n and 
 continues beyond 0.634. There is a 
 weak maximum near 0.53u. The 
 end of the negative slants to an un- 
 usual degree. The contour of the 
 weak band is V-shaped like the 
 visible band for solution No. 74. 
 
 76. Diamine Green B. (C.) Sodium salt 
 
 of diphenyl - disazo-phenol-disulpho- 
 amidonaphthol-azo-nitrobenzene. 
 
 NOP 872 PO. Gel s* 
 
 Dull-gray, crystalline powder. In solu- 
 tion bluish green, bluish green. 
 
 3 g. per liter. 
 
 Angle 17.0’. Depth 0 to 0.14 mm. 
 
 Gradual absorption in the orange and 
 red. Very weak absorption in the 
 ultra-violet from 0.20% to about 
 0.384. No visible or photographic 
 absorption between 0.384 and o.6p. 
 General absorption begins about 0.6p. 
 
 77.Congo Brown G. (A.) Sodium salt of 
 
 sulpho - benzene-azo-resorcinol - azo- 
 diphenyl-azo-salicylic acid. 
 
 Figs. 35 and 36, pl. 9; No. 379, S. & J. 
 
 Brown powder. In solution light brown, 
 yellow. 
 
 4.67 g. per liter. 
 
 Angle 27.3’. Depth o to 0.25 mm. 
 
 Absorption in violet, blue, and green. 
 Very hazy at green side. Absorp- 
 tion decreases from 0.20pn to a some- 
 what transparent region around 
 0.2954. Maximum absorption at 
 0.365. Absorption ceases at 0.53. 
 A weaker solution (fig. 36) showed 
 transparency from 0.29p to 0.315p. 
 Absorption from 0.315 to 0.428. 
 Maximum absorption at 0.365, as 
 before. Transparent to yellow, 
 orange, and red. 
 
 78. Congo Brown R. (A.) Sodium salt of 
 
 sulpho-naphthalene-azo-resorcin-azo- 
 diphenyl-azo-salicylic acid. 
 
 Fig. 35, pl. 9; No. 380, S. & J. 
 
 Dark, brownish-red powder. In solu- 
 tion reddish brown, yellow. 
 
 Saturated. 
 
 Angle 29.3’. Depth 0 to 0.27 mm. 
 
34 ATLAS OF ABSORPTION SPECTRA. 
 
 78. Congo Brown R—Continued. 81. Curcumine S—Continued. 
 
 Same visible and photographic absorp- 
 tion as No. 77. The change in the 
 constitution is from benzene to naph- 
 thalene. 
 
 79. Fast Green O. (M.) Dinitroso-resor- 
 
 cinol. (Dioximidoquinone.) 
 Similar to fig. 11, pl. 3; No. 394, S. & J. 
 Grayish-brown powder. In solution 
 deep coffee brown, coffee brown. 
 Saturated (heated). 
 Angle 1° 6’. Depth 0.05 to 0.66 mm. 
 General absorption in violet and blue. 
 Similar absorption to that of solu- 
 tion No. 47. The boundaries of the 
 bands, however, are more definite for 
 solution No. 79 than for solution No. 
 47. From 0.20p to 0.325 the ab- 
 sorption is complete. Absorption de- 
 creases with a long, gradual slope, 
 from 0.325 to a minimum of semi- 
 transparency at 0.4754. Then a 
 weak band with maximum at 0.52u 
 presents itself and continues to 0.54. 
 Only very weak absorption is 
 present from 0.54u to 0.63u. With 
 the same solution and the cell 
 set for 35.1’ and 0.32 mm. the ab- 
 sorption was almost complete from 
 0.20 to 0.30n and then sloped gradu- 
 ally to transparency at 0.4054. The 
 band at 0.52u could not be dis- 
 cerned. 
 
 80. Naphthol Green B. (C.) Ferrous so- 
 
 dium salt of nitroso-B-naphthol-f- 
 monosulphonic acid. 
 
 Fig 10, pl. 3; No. 398, S. & J. 
 
 Dark-green powder. In solution green, 
 light green. 
 
 8.75 g. per liter (boiled). 
 
 Angle 31.2’. Depth 0 to 0.29 mm. 
 
 Absorption in violet and in dark red. 
 Absorption very strong from 0.20u 
 to 0.31n. Then the absorption de- 
 creases very gradually, with a long 
 slant, to 0.455. From 0.455 to the 
 orange the transparency is complete. 
 Absorption begins again in the red. 
 
 81.Curcumine S. (A.) Sodium salt of 
 
 the so-called azoxy - stilbene - disul- 
 phonic acid. 
 
 Fig. 37, pl. 10; No. 399, S. & J. 
 
 Brown powder. In solution yellow, 
 faint yellow. 
 
 Saturated. 
 
 Angle 1° 10’. Depth 0.11 to 0.75 mm. 
 
 Faint absorption in violet. Absorption 
 decreases from 0.20p to 0.2Qn. Trans- 
 parent from 0.29p to 0.34. Weak 
 band from 0.34p to 0.43 with max- 
 imum at 0.39u. Transparent from 
 
 0.434 to 0.63p. 
 
 82. Auramine O. (B.) Hydrochloride of 
 
 amido-tetramethyl-diamido-diphenyl- 
 methane. 
 
 Fig, 43, pl. 11; Nov 425, S..cca. 
 
 Sulphur-yellow powder. In solution 
 yellow, faint yellow. 
 
 Equal volumes of a saturated solution 
 and of water (filtered). 
 
 Angle 42.5’. Depth o to 0.36 mm. 
 
 Strong absorption in violet and indigo. 
 Relatively transparent at 0.224. The 
 continuous background of the spark 
 indicates one band or, at most, two 
 bands from 0.23n to 0.2754. Un- 
 usually transparent from 0.275 to 
 0.345. A pair of partially-resolved 
 intense bands absorb from 0.345 to 
 0.47. Their maxima lie at 0.365u 
 and 0.4254. The intervening, par- 
 tially-transparent spot is near 0.385. 
 The less refrangible band is the more 
 intense and is very round. Trans- 
 parent from 0.470p to 0.63. 
 
 83. Malachite Green. (M.) Oxalate of 
 
 tetramethyl - di- p-amido - triphenyl- 
 carbinol. 
 
 Similar to fig. 46, pl. 12; No. 427, 
 Da hee Le 
 
 Green, metallic, glistening plates. In so- 
 lution greenish blue, greenish blue. 
 
 3.75 g. per liter. 
 
 Angle 25.5’. Depth 0 to 0.21 mm. 
 
 Strong, double band in the orange and 
 clear red. Deep red is transmitted. 
 Similar absorption to that of solution 
 No. 86 from 0.20 to the yellow. All 
 strong lines in the extreme ultra- 
 violet are transmitted freely. Ab- 
 sorption band lies between 0.29 and 
 0.33u. A faint band has its maximum 
 near 0.4254. Strong absorption com- 
 mences at 0.55pm. 
 
 84. Emerald Green. (B.) Sulphate or 
 
 zinc - double - chloride of tetraethyl- 
 diamido-triphenyl-carbinol. 
 
 Similar to fig. 46, pl. 12; No. 428, 
 Sreetis 
 
 Golden, glistening crystals. In solu- 
 tion green, green. 
 
 4.62 g. per liter. 
 
COLORING MATTERS. a5 
 
 84. Emerald Green—Continued. 
 
 Angle 31.2’. Depth 0 to 0.29 mm. 
 
 Compound band in the orange and red 
 with the maximum in the red. The 
 contour is hazy. Similar absorption 
 to solution No. 86 from 0.20, to the 
 yellow, save that the band near 
 0.425 is hardly discernible on the 
 negative. Strong absorption begins 
 at 0.574. For ultra-violet details see 
 No. 83 above. 
 
 85. Light Green F S. (B.) Sodium salt of 
 
 dimethyldibenzyl-diamido-triphenyl- 
 carbinol-trisulphonic acid. 
 
 Similar to fig. 46, pl. 12; No. 434, 
 lB 
 
 Brownish-black powder. In solution 
 green, green. 
 
 to ¢.. per liter. 
 
 Angle 21.3’. Depth 0 to 0.18 mm. 
 
 Strong band in the yellow, orange, and 
 red. Except for concentration, the 
 absorption is the same as that of so- 
 lution No. 86, hence for further de- 
 tails refer to No. 86. 
 
 86. Acid Green, concentrated. (C.) Sodium 
 
 salt of diethyldibenzyl - diamido - tri- 
 phenyl-carbinol-trisulphonic acid. 
 
 Mie oy ol. 12, No. 435, 5. & J. 
 
 Bright-green, dull powder. In solution 
 deep green, green. 
 
 13:43 2. per liter. 
 
 Angle 25.4’. Depth 0 to 0.23 mm. 
 
 Strong band in orange and red with 
 no return to transparency visible. 
 Absorption in violet and blue. Ab- 
 sorption decreases from 0.20 to 
 about 0.2754. Then a strong band 
 begins, having its maximum near 
 0.32u and returning abruptly to 
 transparency at 0.34. Transparent 
 from 0.34 to 0.39». A round band 
 extends from 0.39 to 0.455 with 
 its maximum at 0.4254. Transpar- 
 ent from 0.455p to 0.554. Strong ab- 
 sorption commences at 0.55 and in- 
 creases to complete opacity at 0.63. 
 Weaker solutions show conclusively 
 the transparent region around 0.275u 
 and also that the band at 0.425 van- 
 ishes most readily. 
 
 87. Fuchsine. (M.) Mixture of hydro- 
 
 chloride or acetate of pararosaniline 
 and rosaniline. 
 Fig. 48, pi 12 No. 448, 5. & J. 
 Green, crystalline powder. In solution 
 deep red, red. 
 
 87. Fuchsine—Continued. 
 
 Angle 21.3’. Depth 0 to 0.18 mm. 
 
 Intense band in blue-green and green. 
 All lines near 0.234 and from 0.25 
 to 0.26u are freely transmitted. The 
 background indicates a band with 
 its maximum at 0.2854 and extend- 
 ing from 0.27p to 0.305. Transpar- 
 ent from 0.3054 to O.45u. Very 
 strong absorption from 0.454 to 
 0.575 with maximum near 0.53». 
 There are probably two unresolved 
 bands of which the more refrangible 
 is the weaker. Transparent from 
 0.575 to 0.63u. A layer about I mm. 
 deep limited the more refrangible, 
 transparent region to the interval 
 from 0.35 to 0.39p. 
 
 88. New Magenta. (O.) Hydrochloride of 
 
 triamido-tritolyl-carbinol. 
 
 Fig. 50; pli 13; No. 449, 5.& J. 
 
 Beetle-green powder. In solution red, 
 bluish red. 
 
 6 g. per liter. 
 
 Angle 31.2’. Depth 0 to 0.29 mm. 
 
 Strong band in the green, steeper on 
 the yellow side, and suggesting -a 
 sharp band superposed upon a 
 weaker one. The band extends from 
 about 0.44 to 0.56% with its maxi- 
 mum tear 0.52u. Transparent from 
 0.56% to 0.63p. 
 
 89. Dahlia. (B.) Mixture of the hydro- 
 
 chlorides or acetates of the mono- 
 di- or tri-methyl (or ethyl) rosani- 
 lines and pararosanilines. 
 
 Fig. 69, pl. 18; No. 450, S. & J. 
 
 Green, lumpy powder. In solution deep 
 blue, reddish violet. 
 
 257-9. per liter, 
 
 Angle 23.4’. Depth 0 to 0.21 mm. 
 
 Absorption commences in the _ blue- 
 green, has its maximum in the green- 
 yellow, and decreases gradually into 
 the red. Transparent to deep red. 
 Absorption in ultra-violet is weak. 
 A band which is definite on the more 
 refrangible edge commences at 0.48 
 and increases to a maximum at 
 0.52u. A weak, unresolved com- 
 panion joins the last one near 0.574 
 and fades away at 0.62p. 
 
 go. Crystal Violet. (B.) Hydrochloride of 
 
 hexamethyl-pararosaniline. 
 Sima to fi7.,00, ploi7: No. 452, 
 cs Na aad 
 
36 ATLAS OF ABSORPTION SPECTRA. 
 
 go. Crystal Violet—Continued. 93. Methyl Green OO0O—Continued. 
 
 Cantharides glistening crystals. In so- 
 lution violet, violet. 
 
 1.38 g. per liter. 
 
 Angle 42.5’. Depth 0 to 0.36 mm. 
 
 The absorption is the same as that ex- 
 hibited by solution No. 92, hence see 
 the description given below. 
 
 gt. Ethyl Violet. (B.) Hydrochloride of 
 
 hexaethyl pararosaniline. 
 
 Fig. 64, pl..16; No. 453, S. & J. 
 
 Green, crystalline powder. In solution 
 pure, deep blue, pinkish blue. 
 
 2.7% ©, per liter: 
 
 Angle 27.3’. Depth 0 to 0.25 mm. 
 
 Intense absorption in the green. Very 
 sharp and abrupt on the blue side 
 but indefinite on the red border. 
 Strong lines in the ultra-violet are 
 transmitted pretty freely. Relative 
 transparency in the vicinity of 0.265. 
 Absorption ceases about 0.3Ip and 
 from this wave-length to 0.495u 
 transparency obtains. At 0.495 an 
 intense band having its maximum at 
 0.5254 begins. About 0.585 the ab- 
 sorption becomes relatively weak and 
 diffuse and continues thus to 0.63. 
 
 92. Methyl Violet 6 B. (A.) Chiefly a mix- 
 
 ture of the hydrochlorides of benzyl- 
 pentamethylpararosaniline and hexa- 
 methylpararosaniline. 
 
 Fig. 66, pl. 17; No. 454, S. & J. 
 
 Metallic, glistening powder. In solu- 
 tion blue, reddish blue. 
 
 25°e. per liter, 
 
 Angle 31.2’. Depth 0 to 0.29 mm. 
 
 Transmits only blue and pure red in 
 concentrated solution. The solution 
 described below showed two bands, 
 the more intense in the green-yellow 
 and the weaker in the orange. All 
 strong ultra-violet lines are trans- 
 mitted. The chief band starts at 
 0.50u, has its maximum at 0.535p, 
 and joins its companion about 0.57. 
 The weaker band has its maximum 
 at 0.595» and fades away at 0.615». 
 Transparent from 0.62% to beyond 
 0.63). 
 
 pe 
 93. Methyl Green OO. (By.) Zinc-double- 
 
 chloride of hepta-methyl-pararosani- 
 line-chloride. 
 
 Similar -to -fig: 47, pl. 2232No. 460, 
 tee ae F 
 
 Green crystals. In solution greenish 
 blue, greenish blue. 
 
 6 g. per liter. 
 
 Angle 19.5’. Depth 0 to 0.18 mm. 
 
 Band in violet and blue, also strong 
 absorption in orange and red. The 
 band in the orange is partly sepa- 
 rated from the stronger band whose 
 intensity increases to, and beyond, 
 0.634. With due allowance for dif- 
 ferences in concentration, it ap- 
 pears that the absorption is, in 
 toto, the same as that shown by 
 solution No. 94. Absorption de- 
 creases from 0.20p to a region of 
 less intense absorption at 0.28p. 
 Then follows a strong band with 
 maximum at 0.3154. A band from 
 0.3754 to 0.445y has its maximum 
 at 0.415u. The yellow and orange 
 band begins at 0.515p. 
 
 94. Methyl Green. Zinc-double-chloride of 
 
 ethylhexamethyl - pararosaniline bro- 
 mide. 
 
 Fig 47, pl. 12; No. 461, S. & J. 
 
 Moss-green, crystalline powder. In 
 solution bluish green, bluish green. 
 
 20 g. per liter. 
 
 Angle 19.5’. Depth 0 to 0.18 mm. 
 
 Band in violet and blue, also strong 
 absorption in orange and red. Trans- 
 mits green and yellow-green. Band 
 from 0.36u to 0.454 with maximum 
 at 0.4154. This band is steeper on 
 its green side. Very transparent 
 from 0.45u to 0.495. From 0.495p 
 the absorption is intense and no re- 
 turn to transparency can be seen at 
 0.634. The band at 0.415 disap- 
 pears first on dilution. 
 
 95. Fuchsine S. (B.) Mixture of the so- 
 
 dium or ammonium salts of the tri- 
 sulphonic acids of rosaniline and 
 pararosaniline. 
 
 Fig. 53, pl. 143 No. 462, S, sccele 
 
 Metallic, green, glistening powder. In 
 solution red, red. 
 
 3 g. per liter. 
 
 Angle 23.4’. Depth 0 to 0.21 mm. 
 
 Strong absorption in the blue-green 
 and green. The middle of the first 
 transparent region is about 0.265p. 
 A weak absorption band has its 
 maximum near 0.295u. The visible 
 band commences at 0.475», has its 
 maximum about 0.535, and ends at 
 0.5754. Transparent from 0.575 to 
 
 0.63pm. 
 
99. China Blue. 
 
 COLORING 
 
 96. Red Violet 5 R S. (B.) Sodium salt of 
 
 ethylrosaniline-sulphonic acid. 
 
 i202, pl. 16; No. 463, S. & J. 
 
 Brownish - violet, metallic, glistening 
 lumps. In solution brownish red, 
 brownish red. 
 
 Saturated. 
 
 Angle 58.5’. Depth 0 to 0.54 mm. 
 
 General absorption in the green, yel- 
 low, and orange. The ultra-violet 
 absorption is complete from 0.20p 
 to 0.364. Absorption decreases 
 gradually from 0.36 to a minimum 
 of general absorption near 0.47». A 
 weak band has its maximum about 
 0.525u. The marked slant of the end 
 of the negative shows the presence 
 of appreciable general absorption in 
 the yellow and orange. Red is trans- 
 mitted. 
 
 O72eikali Blue 6 B: (A. A. C.) Sodium 
 
 salt of triphenyl-p-rosaniline - mono- 
 sulphonic acid. 
 
 Pie 72, pl. 18; No: 476,.S. &J. 
 
 Blue powder. In solution blue, deli- 
 cate blue. 
 
 12.5 g. per liter (heated). 
 
 Angle 23.4’. Depth 0 to 0.21 mm. 
 
 Strong absorption in yellow, orange, 
 and red. Intense, continuous absorp- 
 tion from 0.20u to 0.32n. Abrupt 
 decrease in absorption from 0.32p to 
 transparency at 0.3454. Transparent 
 from 0.345 to 0.5Ip. Strong ab- 
 sorption from 0.51p to beyond 0.63. 
 No decrease in absorption as far as 
 0.63u. The apparent increase in ab- 
 sorption near 0.624 is due to the 
 relative diminution of sensitiveness 
 of the photographic emulsion. 
 
 98. Methyl Blue. (O.) Sodium salt of tri- 
 
 phenyl - pararosaniline - trisulphonic 
 acid. 
 
 Similar to fig. 71, pl. 18; No. 479, 
 ames 
 
 Dark-blue powder. In solution deep, 
 bright blue, blue. 
 
 6.89 g. per liter. 
 
 Angle 21.3’. Depth o to 0.18 mm. 
 
 Strong absorption in the yellow, orange, 
 and red. The description for solu- 
 tion No. 99 holds here quantitatively. 
 
 (A.) Sodium salt of the 
 
 trisulphonic acid of triphenylrosani- 
 
 line and triphenylpararosaniline. 
 Fig: 71, pl. 18; No. 480, S. & J. 
 
 MATTERS. 
 
 3/ 
 
 99. China Blue—Continued. 
 
 TOO. 
 
 IOI. 
 
 I02. 
 
 Coppery flakes. In solution blue, blue. 
 
 3.57 g. per liter (filtered). 
 
 Angle 23.4’. Depth 0 to 0.21 mm. 
 
 A hazy-edged band begins in the green 
 and continues into the red. The 
 strong lines around 0.255 are trans- 
 mitted by the deepest layer of liquid. 
 Absorption is more or less uniform 
 from 0.20pu to 0.32 and then shades 
 off to transparency at 0.3454. Trans- 
 parent from 0.345u to 0.505. Then 
 a band starts and continues with un- 
 diminished intensity to 0.63. 
 
 Coralline Red. Dioxy-amido-triphenyl- 
 carbidrid. 
 
 Fig. 49, pl. 13; No. 484, S. & J. 
 
 Reddish-brown lumps. In solution red, 
 salmon pink. 
 
 11.25 g. per liter (heated). 
 
 Angle 19.5’. Depth o to 0.18 mm. 
 
 Sharp band in blue and green. Very 
 definite at yellow side with maxi- 
 mum in green-yellow. Rather strong 
 absorption from 0.20p to 0.27p, then 
 a decrease to transparency at 0.315p. 
 Strong absorption from 0.445 to 
 0.5574 with maximum at 0.527n. 
 Probably two unresolved bands with 
 the weaker component at the more 
 refrangible side. Transparent from 
 0.557» to 0.63. 
 
 Night Blue. (B.) Hydrochloride of 
 p-tolyltetraethyl-triamido - diphenyl- 
 a-naphthyl-carbinol. 
 
 Similar to fig. 70, pl. 18; No. 480, 
 tl 
 
 Violet, bronzy powder. In solution 
 bright blue, blue. 
 
 2/31 °o. per liter. 
 
 Angle 23.4’. Depth 0 to 0.21 mm. 
 
 Absorption in the yellow, orange, and 
 red. The limit at the green side is 
 steep and the curve is flat in the 
 longer wave-lengths. The visible re- 
 gion of absorption begins about 
 0.5254. For the ultra-violet absorp- 
 tion see fig. 70. 
 
 Victoria Blue 4 R. (B.) Hydro- 
 chloride of phenylpenta-methyl-tri- 
 amido -dipheny] - a - naphthyl - car- 
 binol. 
 
 Pie. Zo, pl. 15; No. 490, 5. & J. 
 
 Bronzy, glistening powder. In solution 
 deep blue, reddish blue. 
 
 2.78 g. per liter (heated). 
 
 Angle 27.3’. Depth 0 to 0.25 mm. 
 
38 
 
 102. 
 
 103. 
 
 104. 
 
 ATLAS OF ABSORPTION SPECTRA. 
 
 Victoria Blue 4 R—Continued. 
 
 Hazy-edged absorption in yellow and 
 orange. The red is only partially 
 absorbed. Comparatively weak ab- 
 sorption decreases steadily from 
 0.20n to about 0.3354. A band com- 
 mences at 0.495y and continues to a 
 maximum at 0.53u. From this point 
 the band shades off gently towards 
 the red. (The apparent increase of 
 absorption at 0.624 is probably due 
 to the increasing lack of sensitive- 
 ness of the plate.) 
 
 Rhodamine B. (B.) Hydrochloride of 
 diethyl-m-amido-phenol-phthaleine. 
 
 Figs 65,0ph127 > Now 504,.c3.c0ce Je 
 
 Reddish-violet powder. In solution 
 bluish red, violet. 
 
 7.5.8. per jiter, 
 
 Angle 42.5’. Depth o to 0.36 mm. 
 
 Two distinct bands, the one in the yel- 
 low-orange and the other in the 
 green-yellow. Eye observations, 
 changes in concentration, and differ- 
 ent makes of films show that the 
 more refrangible band is the more 
 intense. Fluorescent solution. Ab- 
 sorption decreases gradually from 
 0.20p to an indefinite limit near 0.32u. 
 Strong absorption from 0.494n to 
 about 0.594. The maxima are at 
 0.524 and 0.5574 with the inter- 
 vening minimum of absorption at 
 0.54u. Transparent beyond the 
 orange band into the red. 
 
 Fast Acid Violet B. (M.) Sodium 
 salt of diphenyl - m - amido-phenol- 
 phthalein sulphonic acid. 
 
 Fig. 63, pl. 16; No. 506, S. & J. 
 
 Maroon powder. In solution bluish 
 red, pink. 
 
 3 2300 Det uiiter. 
 
 Angle 27.3’. Depth o to 0.25 mm. 
 
 Absorption band in the green-yellow. 
 This band is comparatively definite 
 on the green side and has a shadowy 
 companion on the red side. General 
 absorption continues well into the 
 orange-red. All strong lines in the 
 ultra-violet are transmitted. The 
 ultra-violet absorption ends about 
 0.33u. The visible band begins at 
 0.5054 and has its maximum near 
 0.53u. The less refrangible limit is 
 indeterminate. The essential differ- 
 ence between the spectrograms for 
 solutions Nos. 104 and 106 is that 
 
 104. Fast Acid Violet B—Continued. 
 
 105. 
 
 100. 
 
 107. 
 
 for the former the visible band is 
 asymmetric, whereas for the latter 
 it is symmetric. 
 
 Fast Acid Violet A 2 R. (M.) Sodium 
 salt of di-o-tolyl - m - amido-phenol- 
 phthalein-sulphonic acid. 
 
 Similar to fig. 19, pl. 5; No. 507, S. & J. 
 
 Violet-red powder. In solution red, 
 pink. 
 
 4.67 g. per liter. 
 
 Angle 23.4’. Depth o to 0.21 mm. 
 
 Very narrow, definite band in the 
 green. All strong ultra-violet lines 
 are transmitted. The ultra-violet ab- 
 sorption ends about 0.335. The 
 visible band begins at 0.495p, has its 
 maximum at 0.525, and ends near 
 0.57n. The slanting end of the spec- 
 trogram indicates general absorption 
 in the deep yellow. The green band 
 for this solution is of the same type 
 as the corresponding one for No. 
 104, although it is much less asym- 
 metric, and therefore it resembles 
 more closely No. 106. The spectrum 
 of solution No. 105 is best described 
 as a transition form between Nos. 
 104 and 106. Solutions Nos. 104 
 and 105 have the same empirical 
 formule. 
 
 Acid Rosamine A. (A.) Sodium salt 
 of di- mesidyl - m- amido - phenol - 
 phthalein-sulphonic acid. 
 
 Fig, 19, pL 5; No. 508s 20g 
 
 Light-red powder. In solution red, 
 pink. 
 
 10 g. per liter. 
 
 Angle 29.3’. Depth 0 to 0.27 mm. 
 
 Single V-shaped band in the green. 
 Weak absorption beginning with ex- 
 tinction at 0.204 and fading gradu- 
 ally to transparency at 0.32u. Ab- 
 sorption band covers the interval 
 from 0.505u to 0.565 with its max- 
 imum at 0.5354. Transparent from 
 0.565p to 0.63p. 
 
 Uranine. (B.) Sodium or potassium 
 salt of fluoresceine. 
 
 Figs. 15 and 16, pl. 4; No. 510, S. & J. 
 
 Yellowish-brown powder. In solution 
 reddish yellow, yellow. 
 
 Intense, narrow band in the blue-green 
 with a weaker companion on its more 
 refrangible side. Very strong, yel- 
 lowish-green fluorescence. 
 
————_ eC 
 
 ; 
 ; 
 t 
 
 
 
 COLORING MATTERS. 39 
 
 107. Uranine—Continued. 
 
 Fig. 16 resulted from a solution of 2 g. 
 per liter. 
 
 Angle 23.4’. Depth 0 to 0.21 mm. Only 
 the stronger band shows. Here it 
 extends from 0.480pn to 0.504p with 
 its maximum at 0.493». 
 
 Fig. 15 corresponds to 2.67 g. per liter. 
 The angle 31.2’ gives a maximum 
 depth of 0.49 mm. Complete trans- 
 parency from 0.330u to 0.443u. The 
 spectrogram shows that the visible 
 region of absorption has roughly 
 parallel sides which are very definite. 
 The visible maximum is at 0.493 
 as before. At the outer edge of the 
 fifth strip the absorption covers the 
 interval from 0.443 to 0.515p. 
 
 A solution of 5 g. per liter, of angle 
 42.5, and of depth o to 0.36 mm., 
 absorbed from 0.432» to 0.518 with 
 the maximum at 0.493p. 
 
 A solution of 20 g. per liter with an 
 angle of 42.5’ caused the ultra-violet 
 and visible absorption bands _ to 
 coalesce, on the third photographic 
 strip, in a semi-transparent region 
 extending roughly from 0.355 to 
 0.3954. Intense absorption from 
 0.395" to 0.5334. The short wave- 
 length boundary is indefinite, but the 
 opposite limit is very sharply de- 
 fined and steep. Maximum absorp- 
 tion at 0.493». 
 
 Tests were made to ascertain whether 
 or not the conditions were favor- 
 able to contamination of the absorp- 
 tion spectra by the fluorescent light. 
 The most dilute solution was illu- 
 minated with intense ultra-violet 
 light and an exposure of five min- 
 utes was given to the photographic 
 film. Full development of the film 
 brought out no trace of previously 
 incident light. Therefore, since the 
 Nernst glower alone was used in 
 making the records of the visible 
 bands and because, in all cases ex- 
 cept one, more concentrated solutions 
 were used, it follows that the spec- 
 trograms are correct representations 
 of the absorption, at least so far 
 as the fluorescent light is concerned. 
 
 108. Eosine, yellowish. (A.) Alkali salts 
 
 of tetrabromo-fluoresceine. 
 Fig. 58, pl. 15; No. 512, S. & J. 
 
 108. 
 
 109. 
 
 ‘ia Or 
 
 Eosine, yellowish—Continued. 
 
 Deep red powder. In solution yellow- 
 ish red, pink. 
 
 20 g. per liter. 
 
 Angle 21.3’. Depth o to 0.18 mm. 
 
 Very strong absorption in blue and 
 green. Faint green fluorescence in- 
 creasing with dilution. Intense ab- 
 sorption from 0.20p to 0.33. The 
 absorption then decreases, first gradu- 
 ally and then steeply, to partial trans- 
 parency at 0.37u. This transparent 
 region continues as far as 0.434». 
 Intense absorption from 0.434 to 
 0.56. From 0.515 to 0.5254 the 
 solution is almost opaque. Two un- 
 resolved bands seem to be present. 
 The more refrangible boundary of 
 the visible absorption is less definite 
 than the opposite side. The latter 
 limit is steep and sharp. Transpar- 
 ent from 0.56 to 0.63. 
 
 Eosine a l’alcool. (B.) Potassium 
 salt of tetrabromo-fluoresceine-ethyl- 
 ether. 
 
 geet, Dis NO. SLA, 3. Os). 
 
 Brown powder mixed with small, 
 green crystals. In solution red, pink. 
 
 4.29 g. per liter (heated). 
 
 Angle 46.8’. Depth 0 to 0.43 mm. 
 
 Sharp, narrow band in green, abrupt 
 on yellow side and diffuse on the 
 blue side due to a faint companion 
 band. Slight greenish-yellow fluo- 
 rescence. Very weak absorption in 
 extreme ultra-violet. Absorption be- 
 gins at 0.4954 and ends at 0.540w. 
 The chief maximum is at 0.525p. 
 Transparent from 0.540p to 0.63p. 
 
 Methyl Eosine. (A.) Potassium salt 
 of dibromodinitro-fluoresceine. 
 
 Similar to fig. 58, pl. 15; No. 515, 
 mee 
 
 Brown, crystalline powder. In solution 
 red, orange. 
 
 10 g. per liter. 
 
 Angle 15.6’. Depth 0 to 0.14 mm. 
 
 Intense band in blue and green. Ap- 
 parently two unresolved bands. Sim- 
 ilar absorption to that of solution 
 No. 108. Absorption is rather com- 
 plete from 0.20u to 0.30 and then 
 decreases to about 0.364. Strong 
 absorption from 0.46 to 0.56u. The 
 principal maximum is at 0.52u. Very 
 transparent from 0.56u to 0.63,. 
 
40 
 
 Ai Te, 
 
 biZ; 
 
 rr, 
 
 ATLAS OF ABSORPTION SPECTRA. 
 
 Eosine, bluish. (B.) Sodium salt of 
 tetraiodo-fluoresceine. 
 
 Similar to fig. 58, pl. 15; No. 517, 
 Pre it fs 
 
 Lavender powder. 
 pink. 
 
 15 g. per liter. 
 
 Angle 21.3’. Depth o to 0.18 mm. 
 
 Intense absorption in the blue-green. 
 Similar absorption to that of solu- 
 tion No. 108. The yellowish-green 
 fluorescence only appears in dilute 
 solutions. Absorption decreases 
 gradually from 0.20 to 0.36u. In- 
 tense absorption from 0.455u to 
 0.555u. Maximum of absorption at 
 0.524. There seem to be two unre- 
 solved bands of which the more re- 
 frangible is a little less intense than 
 its companion. This region of ab- 
 sorption is sharper and steeper at 
 its yellow border. Transparent from 
 0.555 to 0.63p. 
 
 Erythrosine. (M.) Sodium salt of 
 tetraiodo-fluoresceine. 
 
 Fig. 59, pl. 15; No. 517, S. & J. 
 
 Dark-red powder. In solution red, 
 pink. 
 
 15 g. per liter. 
 
 Angle 21.3’. Depth o to 0.18 mm. 
 
 Intense absorption in the blue and 
 green. A strong band in the middle 
 with a slightly weaker, unresolved 
 companion on each side. The yel- 
 lowish-green fluorescence only ap- 
 pears in dilute solutions. The re- 
 gion of visible absorption is from 
 0.455" to 0.562u. The chief maxi- 
 mum is about 0.518. The yellow 
 edge of this group of bands is very 
 sharply defined. Transparent from 
 0.562 to 0.63p. 
 
 Cyanosine. (M.) Alkaline salt of 
 tetra - bromodichloro - fluoresceine- 
 methyl-ether. 
 
 Fig: 18, pl. 5; No. 319 5.¢4); 
 
 Brownish-red powder. In solution red, 
 bluish pink. 
 
 Saturated (boiled). 
 
 Angle 25.4’. Depth 0 to 0.23 mm. 
 
 Bind in blue-green and green. Faint, 
 yellowish fluorescence. Strong ab- 
 sorption from 0.493» to 0.553" with 
 its maximum at.0.525u. Transpar- 
 ent from 0.553 to 0.63p. 
 
 In solution red, 
 
 114. Rose Bengal. 
 
 I15. 
 
 116. 
 
 (B.) Alkaline salt of 
 tetraiododichloro-fluoresceine. 
 
 Similar to fig. 59, pl. 15; No. 520, 
 Sk he 
 
 Brown powder. In solution red, orange. 
 
 15 g. per liter. 
 
 Angle 21.3’. Depth 0 to 0.18 mm. 
 
 Double, unresolved pair of bands in 
 green. In amyl alcohol the bands 
 were nearly resolved. Strong ab- 
 sorption from 0.20pn to about 0.33,, 
 except a slight weakening at 0.295. 
 Transparent from 0.33u to 0.48n. 
 Strong absorption from 0.48 to 
 0.575u. Transparent from 0.575» to 
 0.63p. 
 
 Phloxine. (B.) Sodium salt of tetra- 
 bromotetra-chloro-fluoresceine. 
 
 Fig. 60, pl Ths" No, $27, oa 
 
 Brick-red powder. In solution cherry 
 red, pink. 
 
 12.5 ge. per lier, 
 
 Angle 42.5’. Depth 0 to 0.36 mm. 
 
 Intense absorption in the green. Dark- 
 green fluorescence. Visible band lies 
 between 0.458 and 0.574. The max- 
 imum is near 0.5254. For dilute so- 
 lutions the absorption is very much 
 like that shown by fig. 18, except 
 that the contour of the band in the 
 green is sharper than for solution 
 No. 113. 
 
 Galleine. (By.) Pyrogallol-phthalein. 
 
 Similar to fig. 11, pl. 3; No. 525, S.& J. 
 
 Violet brown powder. In solution very 
 dark brown, brown. 
 
 Saturated (heated). 
 
 Angle 58.5’. Depth 0 to 0.54 mm. 
 
 Hazy-edged absorption in the blue- 
 green and green. Absorption is com- 
 paratively strong at 0.20n and de- 
 creases very gradually to semi-trans- 
 parency about 0.4354. Only partial 
 transparency exists between 0.435m 
 and 0.485u. A V-shaped band ab- 
 sorbs from 0.4854 to 0.553u. The 
 maximum is about 0.524. The end 
 of the negative slants a good deal, 
 showing general absorption in the 
 yellow-orange. The spectrogram is 
 like that which would be obtained 
 with a more concentrated solution of 
 No. 47 if it were possible to produce 
 such a condition. 
 
COLORING MATTERS. 
 
 117. Phosphine. (M.) Nitrate of chrysani- 
 
 118. 
 
 line (unsym. diamido - phenyl - acri- 
 dine) and homologues. 
 
 Hig. 32,0 8; Nou 53205, 6. |. 
 
 Orange-yellow powder. In 
 brown, yellow. 
 
 11.25 g. per liter (heated and filtered). 
 
 Angle 27.3’. Depth 0 to 0.25 mm. 
 
 Absorption in violet, blue, and green 
 with hazy limits. Strong absorption 
 from 0.20p to 0.295p, then weaken- 
 ing to semi-transparency at 0.325. 
 Next a band with maximum at 
 0.364. Return to partial transpar- 
 ency at 0.41. Then follow two un- 
 resolved bands with maxima about 
 0.4584 and o.50u. Complete trans- 
 parency from 0.52 to 0.62u. A solu- 
 tion so concentrated as to absorb all 
 the ultra-violet and visible spectrum 
 from 0.20pn to 0.5384 was transpar- 
 ent to 0.63. 
 
 Alizarine Brown. (M.) Trioxyanthra- 
 quinone. 
 
 Similar to fig. 11, pl. 3; No. 538, S.& J. 
 
 Dark-brown powder. In solution dull 
 brown, brown. 
 
 Saturated. 
 
 Angle 35.1’. Depth 0 to 0.32 mm. 
 
 General, indefinite absorption except 
 in the red. Absorption intense and 
 uniform from 0.20p to 0.33. From 
 0.334 the absorption decreases very 
 gradually and nearly linearly to 
 about 0.47p. A very weak band with 
 its maximum at 0.524 exists over 
 and above the intensity minimum of 
 the sensitized film. The end of the 
 negative slopes appreciably, denoting 
 continued general absorption in the 
 orange. No visible weakening of the 
 red. A maximum of transparency is 
 around 0.484. The spectrograms for 
 solutions Nos. 116 and 118 are very 
 similar. 
 
 solution 
 
 119. Alizarine Red S. (B.) Sodium salt of 
 
 alizarine-monosulphonic acid. 
 Fig. 14, pl. 4; No. 546, S. & J. 
 Orange-yellow powder. In 
 reddish yellow, yellow. . 
 12 g. per liter (heated and filtered). 
 Angle 30.0’. Depth 0 to 0.45 mm. 
 Absorption in violet and blue. Opaque 
 from 0.20% to 0.275. Absorption 
 decreases gradually from 0.2754 to 
 partial transparency at 0.377y, and 
 
 solution 
 
 AI 
 
 119. Alizarine Red S—Continued. 
 
 then increases to a maximum at 
 0.424. Absorption ends at 0.485. 
 
 No visible absorption from 0.49 to 
 0.6 
 
 -O3M. 
 120. Alizarine Blue S. (B.) Sodium bisul- 
 
 I2]. 
 
 122. 
 
 phite compound of dioxy - anthra- 
 quinone-B-quinoline. 
 
 Fig, 25D. 72NGe 5695-5, &. be 
 
 Chocolate-brown powder. In solution 
 yellowish brown, brown. 
 
 7.327 2. per liter. 
 
 Angle 58.5’. Depth 0 to 0.54 mm. 
 
 Absorption in violet, blue, and green. 
 The absorption extends into the 
 ultra-violet. Absorption from 0.20u 
 to 0.334 is almost complete save a 
 slight weakening around 0.285. In- 
 tense maximum at 0.315u. Absorp- 
 tion decreases abruptly from _ be- 
 yond 0.33 to transparency at 0.36p. 
 The transparent region is from 
 0.36% to about 0.385. A pair of 
 wide bands absorbs from 0.385 to 
 0.5434. Their maxima are at 0.44u 
 and 0.5174. The intervening mini- 
 mum of absorption is at 0.48n. 
 Transparent from 0.543 to 0.63. 
 The ultra-violet bands remain very 
 intense even when dilution causes 
 the visible bands to disappear. 
 
 Neutral Red. (D. H.) Hydrochloride 
 of dimethyldiamido-toluphenazine. 
 
 Similar to fig 54, pl. 14; No. 580, 
 Se: Ge] 
 
 Dark-green powder. In solution red, 
 pink. 
 
 3 g. per liter. 
 
 Angle 39.0’. Depth 0 to 0.36 mm. 
 
 Band in blue and blue-green, not sharp 
 at edges. Very similar absorption 
 to that of solution No. 122. Slight 
 transparency at 0.23». <A band lies 
 between this point and 0.31% where 
 transparency begins to be complete. 
 An absorption band extends from 
 0.468 to 0.545 with its maximum at 
 0.507n. Transparent from 0.545 to 
 0.63p. 
 
 Phenosafranine. Diamidophenyl-phena- 
 zonium chloride. 
 
 Fie. 54, pl. 14;.No.,583, 9. & J. 
 
 Green, glistening crystals. In solution 
 clear red, pink. 
 
 2.5.2. per. liter. 
 
 Angle 39.0’. Depth 0 to 0.36 mm. 
 
42 
 
 I22. 
 
 125) 
 
 ATLAS OF ABSORPTION SPECTRA. 
 
 Phenosafranine—Continued. 
 
 Band in blue and blue-green, not sharp 
 at edges. The ultra-violet band ends 
 about 0.31~. The visible band ab- 
 sorbs from 0.45u to 0.5454 with 
 maximum at 0.50u. Transparent 
 from 0.545 to 0.63pm. 
 
 . Safranine. (B.) Mixture of diamido- 
 
 phenyl- and tolyl-tolazonium chlo- 
 rides. 
 
 Similar to fig. 54, pl. 14; No. 584, 
 5. |: 
 
 Reddish-brown powder. 
 red, red. 
 
 5 g. per liter. 
 
 Angle 27.3’. Depth 0 to 0.25 mm. 
 
 Definite absorption in blue-green and 
 green. Similar absorption to that 
 of solution No. 122. Strong ab- 
 sorption from 0.20 to 0.28u. Rapid 
 decrease in absorption from 0.28p 
 to 0.324. Absorption begins again 
 at 0.44u, increases to a maximum 
 near 0.495, and then decreases to 
 transparency at 0.5554. Transparent 
 from 0.555 to 0.63. 
 
 In solution 
 
 . Heliotrope 2 B. (A.) Dimethyldiam- 
 
 ido-xylyl - xylophen-azonium chlo- 
 ride. 
 
 Fig. 68, pl. 17; No. 590, S. & J. 
 
 Grayish-green powder. In solution 
 reddish violet, reddish violet. 
 
 7 &. per liter. 
 
 Angle 27.3’. Depth 0 to 0.25 mm. 
 
 Strong band in yellow and orange. 
 Transparent to deep red. Strong 
 absorption from 0.48 to 0.605 with 
 maximum near 0.535u. Increasing 
 transparency from 0.605 into the 
 red. 
 Rosolane O. (M.) Phenyldiamido- 
 phenyl-toluphen-azonium chloride. 
 Similar to fig. 19, pl. 5; No. 5091, 
 Ser |: 
 
 Olive-green powder. In solution deep 
 violet, faint, reddish violet. 
 
 9 g. per liter (warmed and filtered). 
 
 Angle 35.1’. Depth 0 to 0.32 mm. 
 
 Weak band in the green broadening 
 out into general absorption on the 
 red side. Somewhat similar absorp- 
 tion to that of solution No. 106. 
 The visible band is definitely v- 
 shaped and slopes more at its less 
 refrangible side than at its blue 
 boundary. Slight transparency at 
 0.23 is followed by a maximum of 
 
 126. 
 
 126. 
 
 127, 
 
 128. 
 
 
 
 * Spectrogram too indefinite for reproduction, 
 
 Rosolane O—Continued. 
 absorption near 0.27». Absorption 
 ceases about 0.334 and begins again 
 at 0.4954. The latter band has its 
 maximum at 0.525 and fades into 
 general absorption around 0.563,. 
 The end of the positive slants ap- 
 preciably, thus emphasizing the gen- 
 eral absorption in the orange. Trans- 
 parent to the red. 
 
 Nigrosine, soluble. (A.) Sodium salts 
 of sulphonic acids of spirit nigro- 
 sines. 
 
 Somewhat like figs. 20 and 21 of pls. 
 5 and 6, respectively ; No. 602, S. & J. 
 
 Coal-black, glistening lumps. In solu- 
 tion blackish blue, dull blue. 
 
 Saturated. 
 
 Angle 31.2’. Depth 0 to 0.29 mm. 
 
 Very indefinite absorption in the yel- 
 low and orange. The ultra-violet 
 absorption is like that of solution 
 No. 127, while the visible absorp- 
 tion is similar to that of solution 
 No. 46. However, the band at 
 0.528p is incomparably weaker than 
 the corresponding band of solution 
 No. 46. Absorption rather strong 
 between 0.20p and 0.30u. From 0.30 
 the absorption decreases to transpar- 
 ency at 0.354. Different photo- 
 graphic emulsions show a weak 
 band about 0.5284. Absorption 
 continues general into the red, as is 
 shown by the appreciable slant of the 
 end of the negative. 
 
 Naphthalene Red. Mixture of amido- 
 naphthyl-naphthazonium chloride and 
 diamido - naphthyl - naphthazonium 
 chloride. 
 
 Fig, 20, pls; No. 614, Soa. 
 
 Dark-brown powder. In solution red, 
 faint pink. 
 
 Saturated (heated). 
 
 Angle 31.2’. Depth 0 to 0.29 mm. 
 
 Hazy-edged absorption band in the 
 green. The visible band extends 
 from 0.488» to 0.545 with its max- 
 imum at 0.517. The slight inclina- 
 tion at the red end of the negative 
 shows appreciable decrease of trans- 
 parency, between 0.545 and 0.63n, 
 with increase of thickness of absorb- 
 ing layer. 
 
 Alizarine Green B. (D.) Dioxy- 
 naphthazoxonium sulphonate. 
 
 No. 647, S. & J.* 
 
129. Columbia Yellow. 
 
 COLORING 
 
 128. Alizarine Green B—Continued. 
 
 Dark-green powder. In solution dark 
 green, light green. 
 
 20 g. per liter (heated and filtered). 
 
 Angle 31.2’. Depth 0.26 to 0.55 mm. 
 
 General absorption in the violet, 
 orange, and red. The minimum of 
 absorption lies in the green, of 
 course. When the depth was o to 
 0.29 mm., the ultra-violet absorption 
 ended at about 0.355. There is no 
 sharp band in the ultra-violet, but 
 simply one-sided absorption, decreas- 
 ing from 0.20u towards the longer 
 wave-lengths. 
 
 (A.) Ovxidation 
 products of dehydrothiotoluidine-sul- 
 phonic acid or of the latter and 
 primuline together. 
 
 big. 3, pi. 2° No. 663, S. & J. 
 
 Brownish-yellow powder. In solution 
 yellow, light yellow. 
 
 10 g. per liter (warmed). 
 
 Angle 31.2’. Depth 0 to 0.29 mm. 
 
 Weak-edged absorption in violet. Uni- 
 form absorption from 0.20, to about 
 0.36u. Then a steady decrease in 
 
 absorption to 0.45. Complete trans- * 
 
 parency from 0.45 to 0.63. 
 
 130. Ouinoline Blue. (G.) No. 664, S. & J. 
 
 Glistening, green crystals. In solution 
 delicate violet, pink. 
 
 Saturated (heated). 
 
 Angle 0°. Depth 134 mm. 
 
 Only the blue and blue-green faintly 
 transmitted. (No photograph was 
 taken for the saturated solution.) 
 When 44 cc. of the saturated solu- 
 tion was diluted to 90 cc. a strong 
 band appeared in the yellow and 
 orange, while the red was freely 
 transmitted. The ultra-violet absorp- 
 tion extends to 0.40 and fades out 
 about 0.424. Weak absorption be- 
 gins at 0.48 and increases to opacity 
 near 0.55. Complete absorption con- 
 tinues to about 0.607. Absorption 
 decreases rapidly from 0.607 to 
 0.634. When 44 cc. of the saturated 
 solution was made up to II2 cc. 
 and a column I5 cm. was used, no 
 definite band could be seen, but 
 only a faint weakening of the 
 orange. The ultra-violet absorp- 
 tion was, however, complete as far 
 as 0.374 and vanished near 0.395p. 
 
 MATTERS. 
 
 (31: 
 
 132. 
 
 162. 
 
 43 
 
 Quinoline Yellow, soluble in water. 
 (A.) Quinoline Yellow O. (M.) 
 Sodium salt of the sulphonic acid 
 (chiefly disulphonic acid) of 
 quinophthalone. 
 
 ligase Ol irs No. 007, 5..60 7}. 
 
 Yellow powder. In solution lemon yel- 
 low, faint yellow. 
 
 17.5 g&. per liter. 
 
 Angle 27.3’. Depth 0 to 0.25 mm. 
 
 Strong band in extreme violet. One- 
 sided absorption in ultra-violet ends 
 about - 0.33n. Transparent region 
 from 0.33u to 0.3454. A band com- 
 mences at 0.345, has its maximum 
 at 0.40n, and joins a narrow, com- 
 panion band at 0.438%. Maximum 
 of little band is about 0.448 and 
 complete transparency extends from 
 0.453 to 0.63n. For a 5-strip nega- 
 tive the absorption only advanced 
 to 0.463). 
 
 Indigo Carmine, dry. Sodium salt of 
 indigotine disulphonic acid. 
 
 No. 692, S. & J. 
 
 Deep-violet powder. 
 blue. 
 
 10 g. per liter. 
 
 Angle 23.4’. Depth 0 to 0.21 mm. 
 
 Transmits green and yellow. Moder- 
 ately intense band in the orange-red, 
 beginning about 0.555 and increas- 
 ing beyond 0.63». General absorp- 
 tion from 0.20n to complete trans- 
 parency at 0.37». 
 
 Acid Magenta S. 
 fig. 53, pl. 14. 
 Dark-green powder. In solution bluish 
 
 red, bluish pink. 
 
 10 2. per liter. 
 
 Angle 15.6’. Depth 0 to 0.14 mm. 
 
 Strong band in the green with abrupt 
 edges. Violet, indigo, orange, and 
 red are transmitted. Similar ab- 
 sorption to that of solution No. 95. 
 Partial transparency in the vicinity 
 of 0.2654. A comparatively weak, 
 narrow band has its maximum near 
 0.295, and absorption ceases about 
 0.3254. An intense region of ab- 
 sorption begins at 0.46, has its max- 
 imum at 0.535u, and ends at 0.58n. 
 Therefore this region slants more at 
 the violet border than at the orange 
 side. The band is very smooth and 
 round. 
 
 In solution blue, 
 
 (A.) Similar to 
 
44 
 
 134. 
 
 ATLAS OF ABSORPTION 
 
 Alizarine Orange. (Powder 80 per 
 cent.) (M.) 
 
 Fig. 24, pl. 6. 
 
 Very deep-purple powder. 
 dark red, red. 
 
 5.83 g. per liter (warmed and filtered). 
 
 Angle 27.3’. Depth 0 to 0.25 mm. 
 
 Weak, shadowy band in the green-yel- 
 low, gradually fading away in the 
 red. The ultra-violet absorption is 
 intense and one-sided, and _ ceases 
 about 0.394. The visible band be- 
 gins near 0.48, has its maximum at 
 0.5254, and fades into general ab- 
 sorption about 0.564. The end of 
 the negative slopes to an unusual 
 extent, showing that the general ab- 
 sorption is relatively strong. 
 
 In solution 
 
 135. Alizarine Red No. 1. 40 per cent. (M.) 
 
 136. 
 
 Similar to fig. 11, pl. 3. 
 
 Yellow paste. In solution deep yel- 
 low, yellow. 
 
 Saturated. 
 
 Angle 31.2’. Depth 0 to 0.29 mm. 
 
 Absorption very weak, general, and in- 
 definite. A few mm. of the solution 
 show complete opacity. The solu- 
 tion looks like a milky but yellow 
 emulsion. The ultra-violet absorp- 
 tion is relatively weak, is quite gen- 
 eral, and fades away to semi-trans- 
 parency near 0.4u. A slight weak- 
 ening of transparency around 0.52 
 may be the fault of the sensitized 
 film. The end of the negative slopes 
 quite enough to indicate continued 
 absorption in the orange. No visible 
 absorption in the red. 
 
 Aurophosphine 4 G. (A.) 
 
 Big. AG, pi. 2. 
 
 Reddish-brown powder. 
 clear yellow, yellow. 
 
 11.67 g. per liter. 
 
 Angle 27.3’. Depth 0 to 0.25 mm. 
 
 Strong absorption in the violet and 
 indigo. Absorption decreases from 
 0.20n to a maximum at 0.2454 and 
 then follows a rounded curve to 
 transparency at 0.3054. Unusual 
 transparency from 0.305 to 0.390. 
 As for p-nitrosodimethyl aniline, so 
 here, all the strong lines between 
 0.324 and 0.363% are transmitted 
 with almost no decrease of inten- 
 sity. A V-shaped band absorbs 
 from 0.390p to 0.470 with its max- 
 
 In solution 
 
 SPECTRA. 
 
 136. Aurophosphine 4 G—Continued. 
 
 imum at 0.4304. Transparent from 
 0.470n to 0.63p. 
 
 137. Brilliant Croceine, blue shade. (M.) 
 
 138. 
 
 139. 
 
 Similar to fig. 52, pl. 13. 
 
 Bright-red powder. In solution red, 
 salmon pink. 
 
 ag. per, liter: 
 
 Angle 25.4’. Depth 0 to 0.23 mm. 
 
 Strong band in blue-green and green. 
 It slopes more on the blue than on 
 the yellow border. Similar absorp- 
 tion to that of solutions Nos. 21 and 
 43. Absorption decreases from 0.20p 
 to a region of partial transparency 
 in the vicinity of 0.29n. A sym- 
 metrical, hazy band absorbs from 
 about 0.305u to 0.3854. A strong 
 band absorbs from 0.458 to 0.558u 
 with its maximum near 0.518n. 
 Transparent to the orange and red. 
 
 Brilliant Purpurine 10 B. (A.) 
 
 Similar to fig. 21, pl. 6. 
 
 Grayish-violet powder. In solution red, 
 bluish red. 
 
 5.83 g. per liter (warmed). 
 
 Angle 23.4’. Depth 0 to 0.21 mm. 
 
 Shadowy band in the green with gen- 
 eral absorption in the yellow and 
 orange. Similar absorption to that 
 of solution No. 46. Absorption de- 
 creases from 0.20u to a semi-trans- 
 parent region around 0.29”. A sym- 
 metrical, hazy band absorbs from 
 about 0.30n to 0.38%. Another band 
 begins near 0.48u, has its maximum 
 at 0.524, and ends at 0.555. The 
 end of the negative slants at an 
 angle of about 30°, thus emphasiz- 
 ing the strong, general absorption 
 in the yellow-orange. 
 
 Carthamin. 
 
 Similar to fig. 13, pl. 3. 
 
 Reddish-brown plates. In 
 brownish red, faint brown. 
 
 Concentrated. 
 
 Angle 31.2’. Depth 0 to 0.29 mm. 
 
 One-sided absorption in the ultra- 
 violet. Absorption similar to that 
 of solution No. 129. Absorption was 
 strong from 0.20u to about 0.34. 
 From this wave-length on, the ab- 
 sorption curve is round and slopes 
 to 0.445 at the edge of the spec- 
 trogram farthest from the compari- 
 son spectrum. Transparent from 
 0.445 to beyond 0.63». The slope 
 
 solution 
 
COLORING 
 
 139. Carthamin—Continued. 
 
 of the blue side of the band is the 
 same as the corresponding region of 
 solution No. 119. 
 
 140. Columbia Fast Scarlet 4 B. (A.) 
 
 Al. 
 
 142. 
 
 143. 
 
 Similar to fig. 26, pl. 7 
 Red powder. In solution yellowish 
 
 red, pink. 
 5.83 g. per liter. 
 Angle 27.3’. Depth 0 to 0.25 mm. 
 
 Broad absorption in the blue, blue- 
 green, and green. The contour is 
 somewhat hazy. The spectrum is 
 almost identical with fig. 26 for solu- 
 tion No. 69, therefore the wave- 
 lengths are not repeated here. 
 
 Dianil Orange G. (M.) 
 
 Fig. 34, pl. 9. 
 
 Brick-red, glistening powder. 
 tion yellowish red, yellow. 
 
 11.67 &. per liter. 
 
 Angle 23.4’. Depth 0 to 0.21 mm. 
 
 Uniform absorption from the blue 
 border of the green to the extreme 
 violet and beyond. Except for slight, 
 wavy regions, the absorption de- 
 creases almost linearly from 0.20p 
 to about 0.53. At this point it ends 
 rather abruptly. Transparent from 
 0.53u to 0.63y. 
 
 Fluoresceine. Tetraoxypthalophenone 
 anhydride CooH1205;+H20. 
 
 Cinnabar-red powder. In solution faint 
 yellow. 
 
 Saturated (boiled). 
 
 Angle 0°. Depth 3.7 mm. 
 
 Weak band in blue and blue-green. 
 Intense, green fluorescence. Absorp- 
 tion complete from 0.20p to 0.25u 
 and then decreases to transparency 
 at 0.2Qu. Weak absorption ex- 
 tends from about 0.46 to 0.505. 
 
 Guinea Carmine B. (A.) 
 
 Similar to fig. 20, pl. 5. 
 
 Brown powder. In solution red, pink. 
 
 Saturated. 
 
 Angle 2° 17’.. Depth 0.26 to 1.51 mm. 
 
 Absorption in green. No lines trans- 
 mitted between 0.20% and 0.273p. 
 (Non-zero depth of liquid.) Weak 
 absorption from 0.273 to 0.33. 
 Transparent from 0.33u to 0.493». 
 A inazy-edged band extends from 
 0.493» to 0.548» with its maximum 
 at 0.5214. Transparent from 0.548 
 to 0.634. The spectrogram for solu- 
 tion No. 143 does not slant at the 
 
 In solu- 
 
 MATTERS. 45 
 143. Guinea Carmine B—Continued. 
 red limit, whereas that for solution 
 No. 127 does. 
 144. Orcein. 
 
 145. 
 
 146. 
 
 Suggested by figs. 20 and 21 of pls. 
 5 and 6, respectively. 
 
 Black powder with reddish tinge. In 
 solution deep red, light red. 
 
 Saturated (heated and filtered). 
 
 Angle 31.2’. Depth 0 to 0.29 mm. 
 
 Weak, narrow band in the yellow. The 
 ultra-violet absorption is similar to 
 that of solution No. 127. The ab- 
 sorption in the visible spectrum is 
 somewhat like that of solution No. 
 46. However, the band in the yel- 
 low is very much weaker and nar- 
 rower for solution No. 144 than for 
 the corresponding band of solution 
 No. 46. Strong absorption from 
 0.202 to 0.27% was followed by a 
 gradual decrease to transparency 
 near 0.334. Transparent from. 0.33u 
 to about 0.5154. A narrow, hazy- 
 edged absorption band, with its 
 maximum at 0.525u, extended from 
 0.515p to 0.5424 approximately. The 
 very marked slant of the end of the 
 spectrogram showed the presence of 
 comparatively intense, general ab- 
 sorption in the orange. 
 
 Soluble Prussian Blue. 
 
 Deep-blue, glistening powder. 
 lution deep blue, blue. 
 
 1.76 g. per liter. 
 
 Angle 21.3’. Depth 0 to 0.18 mm. 
 
 Strong absorption in the _ yellow, 
 orange, and red. Almost opaque 
 from 0.20% to 0.284. Absorption 
 decreases very gradually from 0.28 
 to 0.384. The visible region of ab- 
 sorption begins at 0.505% and con- 
 tinues to 0.63» and beyond. 
 
 Thiogene Brown S. (M.) 
 
 Similar to fig. 11, pl. 3. 
 
 Bluish-black lumps. In solution dull 
 brown, brown. 
 
 Saturated. 
 
 Angle 27.3’. Depth 0 to 0.25 mm. 
 
 General weakening of all the visible 
 spectrum except the blue and red. 
 The solution smells strongly of 
 hydrogen sulphide. (The odor is 
 not so marked for the dry dye.) 
 Similar absorption to that of solu- 
 tion No. 47. Absorption decreases 
 very gradually from 0.20 to about 
 
 In so- 
 
46 
 
 ATLAS OF ABSORPTION SPECTRA. 
 
 146. Thiogene Brown S—Continued. 
 
 0.4In. On both sides of 0.445 the 
 absorption is at a minimum. A 
 very shadowy band absorbs from 
 0.49n to 0.5454. Its maximum is 
 near 0.523u. The end of the nega- 
 tive slants a good deal more than 
 that of solution No. 47, and thus 
 points to the absorption in the yel- 
 low and orange. 
 
 147. Thiogene Orange R. (M.) 
 
 Similar to fig. 12, pl. 3. 
 Brown powder. In solution reddish 
 
 brown, yellow. 
 
 5.83 g. per liter (filtered). 
 Angle 50.7’. Depth 0 to 0.46 mm. 
 Weak absorption in the violet. The 
 
 solution has an unpleasant odor. Its 
 absorption is similar to that of solu- 
 tion No. 30. Absorption is complete 
 from 0.20 to 0.254 and then de- 
 creases with a long, gentle curve to 
 transparency about 0.445. Trans- 
 parent from 0.445 to 0.63. 
 
 MISCELLANEOUS ABSORBING MEDIA. 
 
 148. Acetone, Ethyl Alcohol, Methyl Alco- 
 
 hol, and Water. 
 
 Fig. 87, ‘pla: 
 The depth of the cell was 1.41 cm. for 
 
 each of the liquids studied. Especial 
 care was taken to have the three 
 organic solvents as nearly anhy- 
 drous and as pure as possible. 
 
 The photographic strip nearest to the 
 
 comparison spectrum gives the ab- 
 
 sorption of the column of acetone. | 
 
 The next strip in order corresponds 
 to ethyl alcohol. The third strip per- 
 tains to methyl alcohol and the 
 strip nearest to the numbered scale 
 is the photographic record for dis- 
 tilled water. 
 
 Acetone absorbed all radiations be- 
 
 tween 0.20u and 3282.4 A. U. and 
 the continuous background as far as 
 3302.7 A. U. 
 
 The most refrangible spark line trans- 
 
 mitted by the ethyl alcohol had the 
 wave-length 2265.1 A. U. This 
 liquid transmitted all the strong 
 ultra-violet lines, but it absorbed the 
 continuous background from 0.20 
 to about 0.275p. 
 
 The methyl alcohol transmitted very 
 
 faintly the strong cadmium line at 
 2313.0, but no other radiation of 
 
 148. Acetone, Ethyl Alcohol, ete—Cont’d. 
 
 wave-length less than 2502.1. The 
 continuous background in the ultra- 
 violet, on the contrary, was trans- 
 mitted somewhat more freely by the 
 methyl than by the ethyl alcohol. 
 
 The distilled water was perfectly trans- 
 
 parent to all the radiations in the re- 
 gion photgraphed. 
 
 These results show that even ethyl 
 
 alcohol is not without sufficient ab- 
 sorption in the remote ultra-violet to 
 make it necessary to take this factor 
 into account when columns two or 
 more cm. long are used. 
 
 149. Aesculine. 
 Fig. 73, pl. 19. 
 White powder. In solution colorless. 
 Saturated. 
 Angle 39.0’. Depth o to 0.36 mm. 
 
 No visible absorption. Intense, blue 
 
 fluorescence. Absorption decreases 
 from 0.20% to semi-transparency 
 about 0.26u. Partial transparency 
 from 0.26 to 0.2734. The band 
 with which the fluorescence is prob- 
 ably associated extends from 0.273 
 to 0.363n with the maximum near 
 0.324. Complete transparency from 
 this band to 0.634 and beyond. 
 
 150. Aluminium Chloride, Calcium Bromide, 
 
 and Calcium Chloride. 
 
 Fig. 88, pl. 22. 
 The depth of the cell was 1.41 cm. for 
 
 each of the solutions studied. The 
 photographic strip nearest to the 
 comparison spectrum gives the ab- 
 sorption of the calcium bromide so- 
 lution. The next strip in order corre- 
 sponds to the aluminium chloride. 
 The third strip from the compari- 
 son spectrum pertains to the calcium 
 salt. The remaining strip shows the 
 lack of absorption possessed by dis- 
 tilled water. 
 
 The concentrations of the aluminium 
 
 chloride, calcium bromide, and cal- 
 cium chloride solutions were, re- 
 spectively, 2.75, 4.24, and 4.51 
 normal. The unit used here is the 
 gram-molecular normal; that is, 1 
 liter of solution of unit concen- 
 tration would contain 1 gram 
 molecule of the anhydrous salt. 
 
 The aluminium chloride solution trans- 
 
 mitted faintly all of the strongest 
 
MISCELLANEOUS ABSORBING MEDIA. A7 
 
 150. Alummium Chloride, ete—Continued. 
 lines in the remote ultra-violet, but 
 it absorbed the continuous back- 
 ground from 0.20% to about 0.288,. 
 
 The calcium bromide solution trans- 
 mitted nothing between 0.204 and 
 2748.7. The intensity of this strong 
 cadmium line was greatly diminished. 
 The continuous background began to 
 be perceptible photographically at 
 about 0.313p. ) 
 
 The calcium chloride solution trans- 
 mitted faintly all of the strongest 
 lines in the remote ultra-violet, but 
 it absorbed the continuous back- 
 ground from 0.20 to about 0.280u. 
 
 Consequently there is no very marked 
 difference between the absorptions 
 exerted by the two chlorides. The 
 bromide, on the other hand, pos- 
 sesses much stronger absorption in 
 the ultra-violet region of the spec- 
 trum. 
 
 151. Barium Permanganate. 
 
 The absorption is identical with that 
 of potassium permanganate  solu- 
 tions, having the same concentration 
 in the MnO, ions. See No. 179. 
 
 152. Calcium Bromide. 
 
 See No. 150. 
 153. Calcium Chloride. 
 See No. 150. 
 154.Carborundum and Dia- GW a 
 mond.* Ov 
 Fig. 80, pl. 22. => ec 
 Eight crystalline plates of oO 4 
 carborundum and three © ° 
 of diamond were fastened ) f 
 to a strip of black paper 
 
 parts of a long, slit-like 
 opening in the paper. 
 The carborundum plates 
 varied in color from 
 
 in such a manner as to g 
 bridge across. different 
 
 visible transparency to 8 
 deep blue. The carbons ») j 
 were colorless. The ac- 
 companying sketch shows 3 
 approximately the size, 
 shape, relative positions, 
 and distribution of blue of — Fig. 7. 
 the plates. d, e, and f denote the 
 diamonds. The paper strip was slid 
 over the slit of the spectrograph, par- 
 allel to the length of this opening, 
 and successive exposures were taken. 
 
 
 
 
 
 * Kindly loaned by Mr. L."E. Jewell, 
 
 154. Carborundum and Diamond.—Cont’d. 
 
 The absorption produced by plates 
 a, b, c, d, and e was first photo- 
 graphed, then the absorption of f 
 and g, next that of h and 1, and 
 lastly, that of 7 and k. The spark 
 and glower exposures were 75 sec. 
 and 60 sec., respectively. 
 
 Plate a was uniformly colored a blue 
 
 of moderate intensity. Its absorp- 
 tion is shown by the photographic 
 strip, the outer boundaries of which 
 are numbered 1 and 2. In cases 
 where the crystals were not in con- 
 tact the light passed through be- 
 tween them and produced narrow 
 comparison spectra; for example, 
 the strip between Nos. 2 and 3. 
 
 Plate b was almost colorless with a 
 
 frosted surface. Thickness 0.036 
 mm. Its absorption spectrum is the 
 strip between 3 and 4. 
 
 Plate c had about the same color as 
 
 plate a. Thickness 0.173 mm. Its 
 absorption spectrum is the strip be- 
 tween 5 and 6. 
 
 Plate d was a smooth, colorless car- 
 
 bon. Thickness 0.191 mm. _ Its 
 spectrum is between 6 and 7. ¢ and 
 d were practically in contact. This 
 pair of plates shows how much more 
 transparent to ultra-violet light pure 
 carbon is than a colorless plate of 
 carborundum of comparable thick- 
 ness. Judging by the negative the 
 former transmits no light of wave- 
 length shorter than 2748.7 A. U., 
 whereas the latter absorbs everything 
 shorter than 0.390p. 
 
 Plate e had such an irregular surface 
 
 that the light transmitted by it did 
 not fall upon the sensitized film. 
 Thickness about 0.191 mm. The 
 blank between 10 and 11 is due to 
 translation of the photographic film 
 between the first and second settings. 
 
 Plate f was a diamond with irregulari- 
 
 ties running parallel to the slit. 
 Thickness 0.533 mm. Spectrum be- 
 tween II and 12. 
 
 Plate g was a deeper blue than any of 
 
 the above-mentioned crystals in the 
 pentagon nearer plate f. The wide 
 border, extending around four sides 
 of the blue area, was practically 
 colorless. Thickness 0.602 mm. 
 
 
 
 
 
48 
 
 ATLAS OF ABSORPTION SPECTRA. 
 
 154. Carborundum and Diamond—Cont’d. 
 
 Een. 
 
 Spectrum between 13 and 14. f and 
 g contrast diamond. colorless car- 
 borundum, and blue carborundum 
 with one another. The blank: from 
 14 to 15 marks the second setting 
 of the film. 
 
 Plate h had a delicate, uniform, blue 
 tint. Thickness 0.064 mm. Spec- 
 trum between 16 and 17. 
 
 Plate + was a deeper blue than any of 
 the preceding crystals. Thickness 
 0.345 mm. Spectrum between 18 
 and 19. The blank from 19 to 20 
 corresponds to the third setting of 
 the photographic film. 
 
 The center of plate 7 was as deep in 
 color as the middle of 7 and it was 
 also the thickest plate studied. Thick- 
 ness 0.693 mm. Spectrum between 
 20 and 21. 
 
 Plate k was of a delicate blue color of 
 a slightly deeper hue than plates b 
 and c, except in the corner nearer 7. 
 In the latter place it had about the 
 same tint as plate h. Thickness 
 0.097 mm. Spectrum between 22 
 and 23. 
 
 Chromium Chloride. 
 
 Fig. 79, pl. 20. 
 
 In solution very dark green, green. 
 
 Saturated. 
 
 Angle 50.7’. Depth, from nearly o to 
 0.46 mm. 
 
 Strong absorption in the violet, blue, 
 orange, and red. 
 
 Absorption was complete from 0.20u 
 to 0.3034. The boundary of the 
 ultra-violet band curved around 
 from 0.303 to 0.3284 as the thick- 
 ness of absorbing layer increased 
 from its least to its greatest value. 
 Semi-transparency from 0.328 to 
 0.380n. A wide, round band, with 
 its maximum near 0.4384, absorbed 
 from 0.380n to 0.498. This is fol- 
 lowed by fairly complete transmis- 
 sion from 0.498% to 0.555. The 
 orange and red region of absorp- 
 tion commenced at about 0.555,. 
 
 156. Cobalt Chloride. 
 
 Fig. 78, pl. 20. 
 
 In solution red, rose-pink. 
 
 351.9 g. of anhydrous salt per liter 
 (2.71 normal). 
 
 156. Cobalt Chloride—Continued. 
 
 Angle 58.5’. Depth 0.53 to 1.07 mm. 
 
 One absorption band in the blue-green 
 and another in the deep red.* Ab- 
 sorption was complete from 0.20 -to 
 about 0.2484. The solution was 
 quite transparent from 0.254 to 
 about 0.495u. An absorption band, 
 with its maximum near 0.520, ex- 
 tended from 0.497p to 0.542u. Trans- 
 parent from the boundary of this 
 band as far as the deep red. 
 
 157. Cobalt Chloride and Aluminium 
 
 Chloride. 
 
 Fig. 95, pl. 24. 
 
 The plane-parallel cell was kept at the 
 constant depth of 1.41 cm. 
 
 The successive solutions were made up 
 in the following manner: First, a 
 chosen volume of the mother-solu- 
 tion of cobalt chloride was run from 
 a burette or pipette into a measur- 
 ing flask. Next, a certain amount 
 of the mother-solution of aluminium 
 chloride was run into the same flask 
 and mixed with the solution of the 
 cobalt salt. Finally, distilled water 
 was added to the mixture until the 
 resulting solution filled up the meas- 
 uring flask to its calibration mark. 
 Of course, all the usual precautions 
 necessary to avoid errors due to 
 changes in volume on mixing and to 
 lack of homogeneity were taken. 
 Each solution of the series was made 
 up to the same volume and con- 
 tained the same amount of cobalt 
 chloride. On the other hand, the 
 mass of the dehydrating agent pres- 
 ent changed from one solution to 
 the next. 
 
 The photographic strips nearest to the 
 numbered scale and to the compari- 
 son spectrum correspond, respec- 
 tively, to the solutions which con- 
 tained the least and greatest amounts 
 of the aluminium salt. The inter- 
 vening strips succeed one another in 
 the order of increasing percentages 
 of aluminium chloride. The con- 
 stant concentration of the cobalt 
 chloride in the solutions was 0.271 
 normal. The concentrations of the 
 aluminium chloride in the several 
 
 
 
 *For exhaustive details see “‘Hydrates in Aqueous Solution,” etc. 
 
 Carnegie Institution of Washington. 
 
 Harry C. Jones, Publication No. 60 of the 
 
MISCELLANEOUS ABSORBING MEDIA. 49 
 
 157. Cobalt Chloride, etc.—Continued. 
 
 solutions of the series were 0.000, 
 HIS, 1.304, 7.676, 1.781, 1.887, 
 2.096, and 2.459 normal. 
 
 The solution which contained no dehy- 
 ‘drating agent only absorbed the con- 
 tinuous background from 0.20 to 
 0.23Ip. The band in the blue-green 
 extended from 0.5034 to about 
 0.530p. 
 
 The solution of concentration 2.096, 
 in the aluminium chloride, absorbed 
 the continuous background from 
 0.20n to 0.2884. The band in the 
 blue-green extended from 0.485, to 
 0.555¢- 
 
 The absorption in the yellow and 
 orange is brought out clearly by the 
 photographic strip adjacent to the 
 comparison spectrum. The changes 
 which the bands in the orange and 
 red undergo when the amount of 
 dehydrating agent in the solutions is 
 increased are pronounced and inter- 
 esting, but they are too complicated 
 to admit of discussion in this place.* 
 Similar changes are brought about 
 by other dehydrating agents, such 
 as calcium chloride, for example. 
 
 Iigure 95 illustrates the fact that the 
 absorption bands of a colored salt, 
 so-called, can be widened by the addi- 
 tion of suitable colorless salts as well 
 as by simple increase in concen- 
 tration. 
 
 158. Cobalt Chloride in Acetone. 
 
 Fig. go, pl. 23, and fig. 94, pl. 24. 
 
 Fig. 90 shows the changes in the posi- 
 tions of the centers of the regions 
 of absorption and transmission of 
 cobalt chloride produced by varying 
 the solvent. The depth of the cell 
 was 2.40 cm. Counting from the 
 comparison spectrum towards the 
 opposite side of the spectrogram, the 
 four photographic strips correspond 
 to solutions of anhydrous cobalt 
 chloride in water, in absolute methyl 
 alcohol, in absolute ethyl alcohol, and 
 in anhydrous acetone, respectively. 
 
 The aqueous solution was rosy red. 
 The methyl solution was purple. 
 The color of the ethyl solution was 
 blue with a slight reddish tinge. The 
 solution in acetone was blue with a 
 
 158. Cobalt Chloride in Acetone—Cont’d. 
 
 slight greenish tinge. The concen- 
 trations of the solutions, in the order 
 named, were, respectively, 0.325, 
 0.099, 0.097, and 0.010 normal. 
 
 The aqueous solution absorbed prac- 
 tically all radiations from 0.20p to 
 0.275p. The blue-green band ab- 
 sorbed the region between 0.45 and 
 0.5 5/- 
 
 The solution having methyl alcohol for 
 solvent absorbed all of the ultra- 
 violet from 0.20u to near 0.39n. It 
 then transmitted from 0.39 to 
 0.4954. The next absorption band 
 extended from 0.495p to 0.56u. The 
 faintness of the associated photo- 
 graphic strip shows the presence of 
 appreciable absorption in the yellow. 
 
 Both the ultra-violet absorption and 
 the adjoining region of transmis- 
 sion were very nearly the same for 
 the solution in ethyl alcohol as for 
 that in methyl alcohol. On the con- 
 trary, the third strip gives no indi- 
 cation of return to transparency in 
 the yellow of the band which ab- 
 sorbed all of the green. 
 
 The acetone solution transmitted the 
 region between about 0.384 and 
 0.564, but absorbed all the other 
 radiations which could affect the 
 Seed film. 
 
 The phenomena in the visible spectrum 
 were brought out very clearly by 
 photographing with a Cramer 
 “Trichromatic” plate. The depth of 
 the cell was decreased to 2.00 cm. 
 
 The aqueous solution transmitted 
 from beyond the shorter wave- 
 length end of the plate to 0.46 and 
 again from 0.543 to beyond 0.625u 
 at the other end of the plate. 
 
 The solution in methyl alcohol trans- 
 mitted from 0.387% to 0.495 and 
 again from 0.548 to beyond 0.625n. 
 The intensity of the transmitted 
 light, in the yellow and orange, how- 
 ever, was not as great for the 
 methyl as for the aqueous solution. 
 
 The solution in ethyl alcohol only trans- 
 mitted from 0.385 to 0.497. 
 
 The solution in acetone only trans- 
 mitted from 0.373 to 0.560p. 
 
 
 
 *For exhaustive details see ‘‘Hydrates in Aqueous Solution,” etc. Harry C. Jones, Publication No. 60 of the 
 
 Carnegie Institution of Washington. 
 
50 ATLAS OF ABSORPTION SPECTRA. 
 
 158. Cobalt Chloride in Acetone—Cont’d. 
 
 158. Cobalt Chloride in Acetone—Cont’d. 
 from this wave-length to near 
 
 It is thus seen that the photographic 
 
 center of the band of absorption in 
 the green was displaced by about 
 200 Angstrém units as the solvent 
 was changed from water to methyl 
 alcohol. A still greater displacement 
 was produced by changing from the 
 one alcohol to the other, the concen- 
 trations of the two solutions being 
 very nearly equal. 
 
 The empirical data given above serve 
 to illustrate* the general fact that 
 the position and character of a 
 given region of absorption or of 
 transmission of a chosen colored 
 salt can be varied, in general, over 
 wide ranges by suitable changes in 
 the solvent used. 
 
 Fig. 94 shows the way in which the 
 limits of absorption change when 
 water is added to solutions of anhy- 
 drous cobalt chloride dissolved in 
 
 absolute acetone. The depth of the 
 
 cell was 2 cm. The solutions were 
 made up in the following manner: 
 A certain arbitrary volume of water 
 was poured into a measuring flask 
 and then the flask was filled up to 
 
 its calibration mark by running into’ 
 
 0.552». A strong absorption band 
 commenced at 0.552 and extended 
 into the red. 
 
 The photographic strip pertaining to 
 
 the solution which contained the 
 smallest measured amount of water 
 transmitted from 0.333 to about 
 0.5664. The change in absorption 
 due to the addition of water to the 
 anhydrous mother-solution is, there- 
 fore, more noticeable in the ultra- 
 violet than in the yellow. The photo- 
 graphic boundary of the ultra-violet 
 absorption band changed but little, 
 as the percentage of water present 
 in the solutions increased from 2 to 
 12, and this is due to the intense 
 ultra-violet absorption of the pure 
 acetone. (See No. 148.) On the 
 other hand, acetone possesses no ab- 
 sorption band in the visible spectrum, 
 and hence the limits of transmission 
 in the green and yellow, as shown 
 by the several strips of the spec- 
 trogram, represent correctly the 
 changes in absorption consequent 
 upon the addition of successive in- 
 crements of water. 
 
 it from a burette the requisite amount 159. Cobalt Chloride in Ethyl Alcohol. 
 
 of a mother-solution composed of See No. 158. 
 
 anhydrous cobalt chloride and abso- 160. Cobalt Chloride in Methyl Alcohol. 
 lute acetone. When water is gradu- See No. 158. 
 
 ally added to such a mother-solution 161. Cobalt Glass. 
 
 the resulting liquid changes by de- Fig. 85, pl. 21. 
 
 grees from deep blue through light A plane-parallel sheet of ordinary blue 
 
 blue and then through an almost 
 colorless condition to faint pink. 
 The percentages by volume of the 
 water in the solutions under consid- 
 eration were, 0, 2, 4, 6, 8, 10, and 12. 
 The concentration of the mother- 
 solution was 0.015 normal. 
 
 The photographic strip nearest to the 
 comparison spectrum corresponds to 
 the solution which was anhydrous. 
 The next strip pertains to the solu- 
 tion which contained 2 per cent of 
 water, and so on, across the entire 
 spectrogram. The mother-solution 
 absorbed completely all radiations 
 between 0.20pn and 0.333u. The con- 
 tinuous background was very much 
 weakened as far as about 0.361». 
 The solution transmitted freely 
 
 cobalt-glass was ground to the form 
 of a wedge and then polished. A 
 prism of colorless glass was at- 
 tached at the sides to the cobalt prism 
 with its refracting edge parallel to 
 that of the colored glass. The two 
 wedges were in contact over their 
 hypothenuse planes, and hence the 
 outer plane surfaces were nearly 
 parallel. The object in using the 
 colorless glass wedge was, obviously, 
 to correct for the dispersion of the 
 cobalt-glass prism. The lack of 
 agreement between the contiguous 
 edges of the two photographic strips 
 shows that the angle of the color- 
 less prism ought to have been at 
 least twice as large as that of the 
 blue prism. The angle of the cobalt- 
 
 
 
 
 
 * See also No. 165. 
 
161. 
 
 162. 
 
 MISCELLANEOUS ABSORBING MEDIA. 51 
 
 Cobalt Glass—Continued. 
 glass wedge was approximately 9°. 
 The compound system absorbed all 
 the ultra-violet from 0.20 to 0.325. 
 The boundary of the ultra-violet 
 band does not curve or slant very 
 much with reference to the long axis 
 of the spectrogram because of the 
 absorption of the colorless glass in 
 this region of the spectrum. The 
 cobalt-glass transmits from about 
 0.3274 to 0.497. Beginning at 
 0.497 a region of absorption ex- 
 tends into the red. The most re- 
 frangible band in this region has its 
 maximum near 0.524. The mini- 
 mum of absorption between the band 
 just mentioned and the less refran- 
 gible, neighboring band is at wave- 
 length o.560n. The band in the 
 orange extended into the red beyond 
 the field of view of the spectrograph. 
 These results were tested by using 
 a red-sensitive photographic plate. 
 
 Cobalt Sulphate. 
 
 Similar to fig. 78, pl. 20. 
 
 Reddish crystals. In solution red, sal- 
 mon pink, 
 
 Saturated. 
 
 Angle about 6°. Depth o to about 3.2 
 mm. 
 
 Rather weak absorption in the blue- 
 green. All of the strongest ultra- 
 violet lines were transmitted. The 
 continuous background was absorbed 
 from 0.20% to about 0.255n. The 
 band in the blue-green extended 
 from 0.505 to 0.525 with its center 
 near O.515p. 
 
 . Copper Chloride. 
 
 Fig. 77, pl. 20. 
 
 Dark-green crystals. In solution dark 
 green, yellowish green. 
 
 534-7 g. of anhydrous salt per liter 
 (3.98 normal). 
 
 Angle 19.5’. Depth nearly 0 to 0.18 mm. 
 
 Intense absorption in the red. The 
 solution was remarkable for its 
 strong absorption of the ultra-violet 
 radiations. Absorption was complete 
 from 0.20p to 0.32 at the thinnest 
 part of the wedge. The end of this 
 band curved around from 0.32p to 
 0.40. Transmission was complete 
 from about 0.40» to the orange. 
 
 164. Copper Chloride and Calcium Chlo- 
 
 ride. 
 
 Figs; 024 pl. 23. 
 
 The plane-parallel cell was kept at the 
 constant depth of 1.41 cm. The 
 several solutions were made up as 
 explained under No. 157, which see. 
 The photographic strips nearest to 
 the numbered scale and to the com- 
 parison spectrum correspond, re- 
 spectively, to the solutions which 
 contained the least and _ greatest 
 amounts of the calcium salt. The 
 intervening strips succeed one an- 
 other in the order of increasing per- 
 centages of calcium chloride. The 
 constant concentration of the cop- 
 per chloride in the solutions was 
 0.398 normal. The concentrations 
 of the calcium chloride in the sev- 
 eral solutions of the series were 
 0.000, 0.271, 0.541, 0.812, 1.082, 
 1.353, 1.624, 1.894, 2.165, 2.435, 
 2.706, 2.977, 3.247, 3.518, 3.788, and 
 4.041 normal. The addition of cal- 
 cium chloride to an aqueous solution 
 of copper chloride changes the color 
 of the latter from clear blue, through 
 green, to yellowish green, due to the 
 presence of an absorption band in 
 the red* and to the encroaching of 
 the ultra-violet band upon the violet 
 and blue. 
 
 The solution which contained only 
 copper chloride absorbed all radia- 
 tions from 0.20u to about 0.36Ip. 
 The solution which contained the 
 greatest amount of the dehydrating 
 agent absorbed all radiations from 
 0.20n to about 0.509Qu. Hence, the 
 ultra-violet region of absorption 
 widened by about 1480 Angstrém 
 units when the concentration of the 
 calcium chloride was increased from 
 0.000 to 4.041 normal. The spec- 
 trogram shows clearly how the suc- 
 cessive increments of absorption de- 
 creased as the concentration of the 
 calcium salt increased in arith- 
 metical progression. Other dehy- 
 drating agents, such as aluminium 
 chloride, for example, produce sim- 
 ilar changes in the limits of ab- 
 sorption. 
 
 
 
 
 
 *For exhaustive details see ‘“‘ Hydrates in Aqueous Solution,” etc. Harry C. Jones, Publication No. 60 of the 
 Carnegie Institution of Washington. 
 
52 
 
 ATLAS OF ABSORPTION SPECTRA. 
 
 165. Copper Chloride in Acetone. 
 
 Fig. g1, pl. 23, and fig. 93, pl. 24. 
 
 Fig. 91 shows the changes in the posi- 
 tions of the ends of the regions of 
 absorption and transmission of cop- 
 per chloride produced by varying the 
 solvent. The depth of the cell was 
 1.50 cm. Counting from the com- 
 parison spectrum towards the oppo- 
 site side of the spectrogram, the four 
 photographic strips correspond to 
 solutions of anhydrous copper 
 chloride in absolute acetone, in ab- 
 solute ethyl alcohol, in anhydrous 
 methyl alcohol, and in water, re- 
 spectively. The acetone solution was 
 brownish yellow. The ethyl solution 
 was dark green. ‘The color of the 
 methyl solution was yellowish green. 
 The aqueous solution was blue. The 
 concentrations of the solutions, in 
 the order named, were, respectively, 
 0.022, 0.321, 0.283, and 0.795 normal. 
 
 The aqueous solution absorbed all 
 radiations from 0.20 to 0.387 and 
 from 0.588 into the red. 
 
 The solution having methyl alcohol for 
 solvent absorbed all of the ultra- 
 violet from 0.20u to near 0.462u. It 
 transmitted from 0.4624 to beyond 
 the region of photographic sensibility 
 of the Seed films. 
 
 The solution in ethyl alcohol absorbed 
 from 0.20p to about 0.515 and again 
 from 0.59p into the red. 
 
 The acetone solution absorbed from 
 0.20 to near O.510u. It transmitted 
 from 0.510u to beyond the region of 
 sensibility of the film used. 
 
 These results were supplemented by 
 the aid of a Cramer “Trichromatic” 
 plate. A bluish-green, aqueous solu- 
 tion of concentration 1.590 normal 
 was substituted for the one referred 
 to above. The depth of cell and the 
 concentrations of the three remain- 
 ing solutions were unaltered. This 
 photograph showed that the new 
 aqueous solution transmitted from 
 0.434p to 0.588n, the methyl solution 
 from 0.4624 to beyond 0.625, the 
 ethyl solution from 0.513" to 0.604p, 
 and the acetone solution from 0.510p 
 to beyond 0.625. 
 
 
 
 165. Copper Chloride in Acetone—Cont'd. 
 
 The exposures for the Seed film and 
 the Cramer plate were, respectively, 
 1.5 and 2 minutes long. 
 
 Fig. 93 shows the way in which the 
 limits of absorption change when 
 water is added to solutions of anhy- 
 drous copper chloride dissolved in 
 absolute acetone. The depth of the 
 cell was 2cm. The solutions were 
 made up as explained under No. 158, 
 which see. 
 
 The percentages by volume of the 
 water in the solutions under consid- 
 eration were 0, I, 2, 3, 4, 6, and 8. 
 The concentration of the mother- 
 solution was 0.022 normal. 
 
 The photographic strip nearest to the 
 comparison spectrum corresponds to 
 the solution which was anhydrous. 
 The next strip pertains to the solu- 
 tion which contained 1 per cent of 
 water, etc., across the entire spectro- 
 gram. The mother-solution ab- 
 sorbed completely all radiations from 
 0.20p to 0.5174. The next four solu- 
 tions had a region of transmission 
 the center of which was at 0.436n. 
 This region was followed by an ab- 
 sorption band whose middle was dis- 
 placed towards the ultra-violet as 
 the amount of water in the solutions 
 was increased. For the 1 and 2 per 
 cent solutions the center of the ab- 
 sorption band had the approximate 
 wave-lengths 0.478» and 0.475, re- 
 spectively. The solution which con- 
 tained 8 per cent of water absorbed 
 all radiations from 0.20% to about 
 0.3934 and transmitted from this 
 wave-length to beyond 0.62u. 
 
 169. Copper Chloride in Ethyl Alcohol. 
 
 See No. 165. 
 
 167. Copper Chloride in Methyl Alcohol. 
 
 See No. 165. 
 
 168. Diamond. 
 
 See No. 154. 
 
 169. Erbium Chloride.* 
 
 Fig. ror, pl. 26. In solution very faint 
 pink. 
 
 Concentrated (filtered). 
 
 The solution was poured into a quartz 
 cell, the ends of which were plane 
 and parallel. The cell was succes- 
 sively adjusted to the following 
 
 
 
 * A specimen from the collection of the late Prof. Henry A. Rowland, 
 
MISCELLANEOUS ABSORBING MEDIA. 53 
 
 169. Erbium Chloride—Continued. 
 
 GRpeis, Viz: 0.830189)" 2.43, 1:73, 
 @.04),.2-33,°2,03) and 2.973 cm. In 
 other words, the thickness of the 
 absorbing layer was increased by 3 
 mm. between the successive photo- 
 graphic exposures. As has _ been 
 often remarked by other observers, 
 the solution in question has a very 
 large number of remarkably narrow 
 absorption bands. 
 
 For the depth of 0.83 cm. all of the 
 ultra-violet is absorbed from 0.20p 
 to the cadmium line at 2880.9, while 
 for the depth of 2.93 cm. transmis- 
 sion begins near 0.300n. The wave- 
 lengths of the maxima of the ab- 
 sorption bands, and the essential 
 characteristics of the bands, as ob- 
 tained directly from the original 
 negative, are as follows: 0.325, 
 0.350u, strong with a broad penum- 
 bra on both sides; 0.3555, faint; 
 0.3045, strong; 0.3662u, faint com- 
 panion of the last; 0.3766p, nar- 
 row and faint; 0.3792u, strong and 
 sharp; 0.3875, faint, diffuse band 
 shading off gradually towards the 
 red; 0.4054, weak and_ sharp; 
 0.4075, weak; 0.416p, faint, dif- 
 fuse band shading off towards the 
 red; 0.419p, faint; 0.422, faint and 
 narrow; 0.4274, extremely faint 
 and diffuse band; 0.4425p, faint; 
 0.4504, comparatively strong and 
 narrow with a very faint com- 
 panion at the more refrangible side 
 and with a broad, hazy band near 
 the opposite edge; 0.4675p, very 
 faint; 0.47254, very faint and dif- 
 fuse; 0.480n, extremely faint; 
 0.485, weak; 0.48754, Ccompara- 
 tively strong and narrow; 0.49Ip, 
 wide, hazy band shading off to- 
 wards the red; 0.5186, weak and 
 narrow; 0.5205n, narrow; 0.5235p, 
 strong and narrow; 0.5365, weak 
 and broad; and 0.5413", weak with 
 a broad, diffuse companion on the 
 side nearest to the red. 
 
 171. Glycerine—Continued. 
 
 of the continuous backgrcund as 
 far as about 0.334. The exposure 
 lasted for 1.5 minutes. 
 
 172. Litmus. 
 
 Figs. 83 and 84, pl. 21. 
 
 In solution blue and red for the 
 neutral (or alkaline) and acid con- 
 ditions, respectively. 
 
 Saturated. 
 
 Angle, about 6° for both cases. 
 Depth o to 3.2 mm., approximately, 
 for fig. 83. 
 
 The absorption of the blue solution 
 is suggested by fig. 83. Absorp- 
 tion was practically complete from 
 0.20u% to about 0.284. From this 
 wave-length the absorption band 
 followed a gentle slope to about 
 0.42p for the greatest depth of so- 
 lution. A region of partial trans- 
 parency extended from 0.424 to 
 near 0.496u. A band of absorption 
 began at 0.496» and had its max- 
 imum approximately at 0.53Ip. 
 The spectrogram indicates the ex- 
 istence of intense absorption in the 
 orange and red. 
 
 Fig. 84 gives the photographic record 
 obtained with an acid solution of 
 litmus. This solution absorbed 
 the greater part of the ultra-violet 
 region just as the neutral solution 
 did. On the other hand, the acid 
 solution exerted general absorp- 
 tion in the violet and blue, where- 
 as the neutral solution, of the same 
 depth, transmitted the light of 
 these colors. The maximum of 
 the band in the green was at 0.515 
 for the red solution. The displace- 
 ment of this maximum from 0.53Iu 
 to 0.5154 was probably exaggerated 
 by the variations of sensibility of 
 the photographic films for radia- 
 tions of different wave-lengths. 
 Fig. 84 recorded only weak ab- 
 sorption in the yellow-orange. Red 
 was transmitted. 
 
 173. Methyl Alcohol. 
 
 170. Ethyl Alcohol. See No. 148. 
 See No. 148. 174. Neodymium Ammonium Nitrate. 
 171. Glycerine. Figs. 96, 97, and 98, pl. 25. 
 A plane-parallel layer of glycerine Pink crystals. In solution pink. 
 13.5 mm. deep absorbed all light Concentrated (filtered). 
 of wave-length less than 0.25 and For fig. 96 the solution was poured 
 
 it produced a general weakening into a quartz cell the ends of 
 
ATLAS OF ABSORPTION SPECTRA. 
 
 174. Neodymium Ammonium Nitrate— 
 
 Continued. 
 
 which were plane and parallel. 
 The cell was successively adjusted 
 _to the following depths, viz: 0.53, 
 O.83,. -1103e NES, P1738 (20059 12.33; 
 and 2.63 cm. In other words, the 
 thickness of the absorbing layer 
 was increased by 3 mm. between 
 the successive photographic ex- 
 posures. As has been often re- 
 marked by other observers, the so- 
 lution in question has a large num- 
 ber of unusually narrow absorption 
 bands, some of which are very in- 
 tense and persistent. 
 
 For the depth of 0.53 cm. all of the 
 ultra-violet is absorbed from 0.20p 
 to the zinc line at 3302.7, while for 
 the depth of 2.63 cm. only very 
 faint transmission obtains in the 
 immediate vicinity of 3407.7 A. U. 
 The general characteristics of the 
 most intense bands can be readily 
 seen by referring to fig. 96, hence 
 it will suffice to give the approxi- 
 mate wave-lengths of the absorp- 
 tion bands which were recorded 
 by the original negative. 
 
 The centers of the bands were at 
 
 0.347p¢@;, 0.350H, 0.355H, 0.381p, very 
 faint; 0.418y, faint; 0.4275, sharp ; 
 0.433u, very faint; 0.4437y, dif- 
 fuse; 0.46Ip, faint and diffuse; 
 0.46954, 0.4755¢, faint; 0.4823p, 
 0.50874, O.51I2u, with a hazy 
 boundary at the less refrangible 
 side; 0.520, 0.52254, broad and in- 
 tense; 0.5324, faint; 0.5775, broad 
 and intense, and 0.5925, faint and 
 diffuse. 
 
 Fig. 97 shows the absorption of the 
 same solution when placed in the 
 wedge-shaped cell. The angle of 
 the liquid wedge was 1° 18’ and 
 the depth increased linearly from 
 0.71 mm. to 1.24 mm. Except for 
 the transmission of the strong 
 metallic lines at 2558.0, 2573.1, and 
 2748.7, the ultra-violet absorption 
 is practically complete as far as 
 0.3250n. The negative for fig. 97 
 recorded very faintly all of the ab- 
 sorption bands given above except 
 the ones at 0.347p, 0.350p, 0.38Ip, 
 0.418p, 0.461, and 0.5324p. 
 
 ae 
 
 175. 
 
 176. 
 
 Neodymium Ammonium  Nitrate— 
 Continued, 
 
 The angle of the cell was 39’ for fig. 
 98, so that the thickness of the 
 absorbing layer varied from about 
 o to 0.36 mm. Absorption was 
 complete from 0.20p to 0.2374. The 
 boundary of this region of ab- 
 sorption curved around rather 
 abruptly from 0.2374 to 0.250u as 
 the depth of solution increased 
 from its least to its greatest value. 
 Transmission by the deepest part 
 of the liquid wedge was weakened 
 somewhat from 0.277% to 0.308». 
 Only the intense absorption band 
 at wave-length 5225 A. U. was re- 
 corded by the negative. 
 
 Nickel Nitrate. 
 
 Fig, 81, pluan 
 
 Green crystals. In solution green, 
 light green. 
 
 Saturated. 
 
 Angle, about 6°. Depth 0 to 3.2 mm., 
 approximately. 
 
 Strong absorption in the orange and 
 red, also weaker absorption in the 
 extreme violet. The absorption 
 was nearly complete from 0.20u 
 to about 0.3124. The end of this 
 region of absorption curved 
 around from 0.312u to 0.326n with 
 increasing depth of solution. Un- 
 usual transparency from 0.326pn to 
 0.3744. A symmetrical absorption 
 band, with its maximum at 0.39Ip, 
 extended from 0.374% to 0.408p. 
 Transmission was complete from 
 this point as far as the absorption 
 band in the orange. The sloping 
 end of the spectrogram calls atten- 
 tion to absorption in the orange. 
 
 Nickel Sulphate. 
 
 Fig. 82, pl. 21. 
 
 Green crystals. In solution green, 
 pale green. 
 
 Saturated. 
 
 Angle, about 6°. Greatest depth, 3.2 
 mm., approximately. Absorption 
 in the extreme violet, orange, and 
 red. Using the faint comparison 
 spectrum as a standard of com- 
 parison, it becomes evident that 
 the solution was remarkably trans- 
 parent to the ultra-violet radia- 
 tions from 0.226n to about 0.365. 
 A symmetrical absorption band, 
 
MISCELLANEOUS ABSORBING MEDIA. 55 
 
 176. Nickel Sulphate—Continued. 
 with its maximum at 0.39Ip, ex- 
 tended from 0.3674 to 0.415p. 
 Transmission was complete from 
 
 179. Potassium Permanganate—Continued. 
 10.67/94 periditer: 
 Angle 27.3’. Depth 0 to 0.25 mm. 
 Five distinct bands clearly visible 
 
 this point as far as the absorption 
 band in the orange. A comparison 
 of figs. 81 and 82 is very sugges- 
 tive. Both spectrograms show the 
 same band at wave-length 0.39Ip, 
 but the ultra-violet absorption ex- 
 erted by the nitrate is entirely dif- 
 ferent from that shown by the sul- 
 phate. 
 
 in the green with a very faint com- 
 panion on the blue side. The cen- 
 tral band of the five is a little 
 more intense than its less re- 
 frangible neighbor. Light from the 
 spark decomposes the potassium 
 permanganate so rapidly, with the 
 formation of innumerable small 
 bubbles, that the exposures had 
 
 yy eeicric: Acid. 
 Pie<36, pl. 22. 
 Yellow crystals with greenish hue. 
 In solution yellow, pale yellow. 
 Concentration unknown. 
 Angle 50.7’. Depth o to 0.46 mm. 
 Hazy band in the violet extending 
 
 to be made as follows: Ist. Expose 
 to spark for 25 seconds. 2d. Re- 
 move cell from spectrograph and 
 clean away the bubbles. 3d. Re- 
 place the cell and make another 
 exposure for 25 seconds, etc., three 
 times for each distinct strip of the 
 
 into the ultra-violet. Absorption 
 decreased gradually from 0.20n to 
 partial transparency at 0.275. 
 Semi-transparency from 0.275 to 
 0.300n. A band of absorption, with 
 hazy contour, extended from about 
 0.300 to 0.400p, its maximum being 
 near 0.35pm. 
 
 178. Potassium Chromate. 
 
 Fig. 80, pl. 20. 
 
 Yellow crystals. In solution yel- 
 low, faint yellow. 
 
 Very dilute. 
 
 Angle 50.7’. Change in depth 0.46 
 mm. 
 
 Absorption in the extreme violet ex- 
 tending into the ultra-violet. The 
 most refrangible absorption band 
 only extends from beyond 0.20, to 
 0.226. The solution is noticeably 
 transparent to all radiations from 
 2265.1 A. U. to 2321.2 A. U., inclu- 
 sive of these limits. An intense 
 band extends from 0.227p to 0.300p. 
 This is followed by a region of al- 
 most complete transparency, the 
 middle of which is near 0.316. A 
 
 spectrogram. The absorption at 
 O0.20n 1S weak and decreases to 
 transparency near 0.254. Unusual 
 transparency from 0.254 to 0.2Qp. 
 This fact is brought out in a half- 
 dozen spectrograms of the region. 
 A band of absorption extends 
 roughly from 0.294 to 0.36% with 
 its maximum at the center. The 
 transparency increases to com- 
 pleteness and continues to 0.483». 
 The wave-lengths of the 7 photo- 
 graphic bands are 0.457p, 0.472, 
 0.488, 0.505m, 0.525n, 0.545H5 
 and 0.570u. (Only 5 bands show on 
 the complete spectrogram.) In 
 decreasing order of intensity the 
 three strongest bands are 0.525p, 
 
 0.505 and 0.545p. 
 
 An effort was made to detect the 8 
 
 bands given by Formanek,* but 
 the conditions were not favorable 
 to recording more than seven 
 bands. Formanek’s wave-lengths 
 are “571.0, 547.3 (Hauptstreifen), 
 525.6, 505.4, 487.0, 470.7, 454.4, 
 and 439.5. 
 
 The negative for fig. 75, pl. 19, shows 
 the seven bands. The solution 
 was practically saturated since it 
 contained 50 grams per liter at 
 
 Figs. 74 and 75, pl. 19. room temperature. Here the ultra- 
 
 Grayish-brown crystals with violet violet absorption extends as far as 
 reflex. In solution deep violet, 0.394. For concentrations from 
 violet. 16.67 to 50 grams per liter, and for 
 
 strong band of absorption extends 
 from 0.332 to 0.406u with its max- 
 imum at 0.369». 
 
 179. Potassium Permanganate. 
 
 
 
 
 
 * See J. Formanek, ‘‘Die qualitative Spectralanalyse anorganischer K6rper,” p. 59. 
 
56 
 
 179. 
 
 ATLAS OF ABSORPTION SPECTRA. 
 
 Potassium Permanganate—Continued. 
 the method used, the bands do not 
 shift at all Trichromatic plates 
 were used to see if any photographic 
 
 bands less refrangible than 0.570u 
 
 could be recorded. No evidence of 
 the existence of such bands was pre- 
 sented. 
 
 180. Praseodymium Ammonium Nitrate. 
 
 181. 
 
 Fig. 100, pl. 26. 
 
 Yellowish-green crystals. In solu- 
 tion yellowish green. 
 
 Concentrated (filtered). 
 
 The solution was poured into a 
 quartz cell, the ends of which were 
 plane and parallel. The cell was 
 successively adjusted to the fol- 
 lowing depths, viz: 0.73, 1.03, 1.33, 
 1.63,.-1.93, 223, 2.53; ‘and. 2.83. cm. 
 In other words, the thickness of 
 the absorbing layer was increased 
 by 3 mm. between the successive 
 photographic exposures. 
 
 The solution is remarkable for the 
 comparative narrowness and great 
 intensity of its absorption bands. 
 Absorption was complete from 
 0.202 to about 0.3334 and 0.343n, 
 respectively, for the least and 
 greatest depths of solution investi- 
 gated. The centers of the four in- 
 tense bands which fell within the 
 region of sensitivity of the Seed 
 emulsion were at wave-lengths 
 0.44454, 0.4685, 0.4820n, and 
 0.590u. The least refrangible side 
 of the band at 0.590 does not ap- 
 pear in fig. 100 because the band 
 came very near the limit of sensi- 
 bility of the photographic film em- 
 ployed. 
 
 Sodium Bichromate. 
 
 Suggested by fig. 14, pl. 4. 
 
 Orange-red crystals. In solution 
 yellow, pale yellow. 
 
 Very dilute solution. 
 
 Angle 50.7’. Depth 0 to 0.46 mm. 
 
 181. Sodium Bichromate—Continued. 
 
 The spectrogram differs from fig. 14 
 in having the ultra-violet absorp- 
 tion curve displaced bodily to- 
 wards the region of the shortest 
 wave-lengths. Absorption was 
 practically complete from 0.20 to 
 about 0.274, for all depths. At the 
 thickest part of the liquid wedge 
 absorption was complete from 0.20 
 to 0.40, but both the photographic 
 strip adjacent to the comparison 
 spectrum and the one in the mid- 
 dle of the spectrogram recorded a 
 comparatively narrow band of 
 semi-transparency, the center and 
 maximum of which was near 
 0.3184. This was followed by a 
 strong, round absorption band 
 whose maximum was at 0.36. In 
 other words, there were two round, 
 ultra-violet bands of absorption 
 which coalesced at the wave- 
 length 0.3184. Transmission was 
 complete from 0.40p to 0.63». 
 
 182. Sodium Nitroprussid. 
 
 Fig. 76, pl. 19. 
 
 Garnet crystals. In solution reddish 
 brown, light brown. 
 
 Saturated. 
 
 Angle 1° 45’. Depth 0 to 0.96 mm. 
 
 Weak absorption in violet. Light 
 from the spark decomposes the 
 solution at the very beginning of 
 illumination so that the method 
 used for photographing the ultra- 
 violet absorption of the perman- 
 ganates was not applicable. This 
 difficulty was not overcome. Ab- 
 sorption decreases to about 0.38u, 
 then increases to a weak maximum 
 near 0.396u, and finally decreases 
 to transparency at 0.4284. No 
 selective absorption from 0.43» to 
 0.62p. 
 
 183. Water. See No. 148. 
 
 
 
 * See H. Kayser, ‘Handbuch der Spectroscopie,” v. iii, Pp. 415. 
 
ALPHABETICAL LIST OF ABSORBING MEDIA. 
 
 ALPHABETICAL LIST OF ABSORBING MEDIA. 
 
 
 
 
 
 PAMEETICSEG eater aietaiste ates «ck a cae oat 
 PRETORIALOWDI ie cos vis <o%6 82 3 cen 
 INGICaVCOM, COMC ts cc.c0s 0500s 
 PGI MIGPENtA Oss. - occ ne = - sss 
 [NCIC MMVOSADIING A... ces cece 
 INPRRRUIGHIGIT ont ses sce s seas wes 
 PATIMEN BUC Sec ccc ees ceisces 
 AMIZATING BTOWN....0.0e640000 
 Alizarine Green B.............- 
 Alizarine Orange. (Powder 80%) 
 Alizarine Red No. 1, 40%...... 
 Alizarine Red S.ci as cs ccs cee 
 PAUIELP SUE TG ESele.s cs 0c 000 278 acs 
 Aluminium Chloride........... 
 Amidonaphtholdisulphonic 
 Acid H 
 Anthracene Red.........2scs¢ 
 Anthracene Yellow C..........- 
 i) ofcbeetaaycocol 0 5a ae eae 
 PMRIGAMRCH eds cere. fo o.5 hc we ss 
 Aurophosphine 4°G.......0..6.- 
 PACH GIOW sxc.) 5 <7 4 oe 8 20 
 
 see ere ere eee e eee eee ens 
 
 Barium Permanganate......... 
 
 WRENZOAZUTING.. «cs sec ss cv ccees 
 Benzopurpurine B............. 
 Benzopurpurine 6 B.........:. 
 Benzopurpurine 10 B.......... 
 Biebrich Scarlet... 5.2.22. 2 
 ISISTAAT COMO TOWN . 6.005080 2 aims 
 PE WISRAGK ON «fs = 5.622 9 68 sie os oa 
 PR ORAS AUN Ea crc ip csp es (cisiere oa 
 BrtantCongo Re. cece esse 
 Brilliant Croceine, blue shade.. 
 Brilliant Orange G...... POR See 
 Brilliant Purpurine 10 B....... 
 Brolliant’Purpurine R,.........- 
 Cateitim: Bromide: ¢< 646s 06 on. 
 Calcium Chioride........- 
 
 Carborundum. .. 
 
 Cy 
 
 Chromotrope 6 B...... 0020+... 
 CO iney eI: Cee aren 5 6, whic’. 016 a)ls\ arias 
 ey SOMMMLGS ris cueie. sce. ce crouse so 
 Cloth Red G..... DO eA ESE 
 Cloth Red 3 GA... 
 ott SaeO ei cie's os. ciscteatoes acts 
 Cobalt Chloride 
 Cobalt Chloride and Aluminium 
 
 OPIN 2 a: 0 v5 «.clc« cate e wee 
 
 es 
 
 Cobalt Chloride in Ethyl Alcohol. 
 
 Cobalt Chloride in Methyl Alcohol) 
 
 Page 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 57 
 
 
 
 
 
 
 
 No.| Pl. | Fig. 
 148 | 22 87 
 ADs erteralsneres 
 86] 12 46 
 Tig so lavereueiierehens 
 I0o6| 5 19 
 149) 19 TS 
 120) 7 28 
 118 wees 
 128 aves 
 134| 6 | 24 
 135 Sere 
 TI9g/ 4 14 
 97| 18 | 72 
 150 | 22 88 
 ped a I 
 (SAG Goll 
 53 eerlevee 
 82] II 43 
 8 | 10 39 
 £36,| 52 45 
 eis emailer 
 GRAN AE ee BA 
 T4| 2 9 
 Be Naceus ailtgcees 
 BT ers cee 2s 
 74 
 aad We 75 
 7S lovee ilhe\ieies 
 stile Som aoe 
 Valle iol |e 
 74| 6 22 
 AQiNiares ail\sieve = 
 54| 2 7 
 Dios ate cil) wd 
 TO) be etal enscas 
 yA Mieien lene lar 
 Dial aes lenge 
 I5| 8 31 
 ESO acetal iveuets 
 69) j-7 26 
 152] 22 88 
 153] 22 88 
 I54| 22 89 
 ESO ae scilis oats 
 99| 18 | 71 
 155 | 20 79 
 B39 2 8 
 Allain 
 Ties 7 
 45) 7 25 
 47| 3 II 
 46| 6 7a 
 156} 20 78 
 157 | 24 95 
 158 ‘fee ag 
 24) 94 
 23} 90 
 ae 24) 94 
 160 2 9° 
 24) 94 
 FOX) 2r 85 
 EOD aielereillsiee « 
 
 
 
 
 
 
 
 GOCOINING: Eset teenie cle cco se.510 
 Columbia Fast Scarlet 4 B..... 
 Columbia WY ellow,a- Gi cee ssscns , 
 
 Gongo Brown! Ge. .-s-e-~ oss 
 
 Congo Brown R............... 
 Congo Cormth.. 0206265 +05s00- 
 omic Comin (8 aut ciao, Selduias 
 Congo Orange G.. 2. s..-6-5 04. 
 Congo Oranve Kove c cae ac «sce 
 (Qemyye Ieee» hese womoane aoc 
 Congo mmbinei rics <\0 0h < olor 
 Copper, Chloridertic .«c-1)-'2 -<0 6 
 Copper Chloride and Calcium 
 
 (Ginleva telat. BG Ro cemoe Boman 
 
 Copper Chloride in Acetone.... 
 
 Copper Chloride in Ethy! Alcohol. 
 
 Copper Chloride in Methyl 
 ICOROMME eee a sies «sie credies 
 Coralline= Rednis.c0 «.<,<4 aoe see 
 Cresotine Yellow G..< s+... 00. 
 Crystal Ponceau 6 R........... 
 Geral VAONehsodpagaseebGoene 
 (Guarcrme ine’ .. crete os 2-5 ees) eri 
 Ciureumine Seecaeihs oalnec eslenls 
 (Cy ANOSING an eta eseoire suet 
 Dalia cetera ee eyelets <istevois steae | one 
 Deltapurpurine '§.6.--....>.... 
 Diamme Black BYOs... oss... 
 Diamine Green. Balen <s.<02. 
 Diamime Red Bisco ca oerece,scenyerc at 
 iB; eyeser eon acme Bh clgsormasonoce: 
 Dia monGerr orcas a nels, sete vo stcas 
 Dian! Orance! Giese oss ss 
 Dian Yellows RAs a. cle. scien 
 Emerald (Greens. a. vere oct a ses 
 
 Erythrosine. cr etter ste e)s..c\s ess.) 
 Ethyl Alcoholic: 5 c2ran. «eshte ss 
 BthyVioletx. cee ctor ee 
 Fast Acid Violet A 2 R....-.... 
 FastvAcids Violet Beasee. cee nee: 
 Mase Brows10s.05 ccc ads ois sie oles ¢ 
 Fast Green O 
 Bist REG Aso ta ars calcee es 
 Hasty Reg sextrarere salans< sce ss 
 Pastaviellow mec nisi oct sana: 
 
 CC ee) 
 
 Ce ee 
 
 CV COTIBO re oak alae a vi ave, aoe 
 Guines Cammtine B.. oot..5 0 ass. 
 Eieliotrope 2 Bos... oe ecacvisnes 
 Indigo Carmine, dry........... 
 Janus Green 
 
 Ce 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 No.| Pl. | Fig. 
 20 
 LAO, Fe reys eset es 
 129) 3 13 
 35 
 TT"9 | 36 
 78| 9} 35 
 7 Meal etiops allie, silage 
 60} 6 23 
 56) 9 33 
 OB accede |i. crane 
 SOils tealts acer. 
 OL Wia'sta ills onsp= 
 163| 20 77 
 164] 23 92 
 165 ‘- “i 
 24) 93 
 166 { Ee a 
 24) 93 
 23 On 
 ii ee 93 
 Ioo | 13 49 
 eiieScalesor 
 18 |. aes 
 go seo 
 30] 3 12 
 tea | aif) 37 
 LIZhy 5 18 
 89 | 18 69 
 OGslereetelesersye 
 TZ lees. 
 A Oilekeasie'| ai vere 
 BG lage eset seate 
 68 | 16 61 
 168 | 22 89 
 T4I ri = Ot 
 40 |. >» 3 
 841%... 3/7 
 23)|. 8 29 
 21} 13 52 
 Tog; 5 17 
 Ty |eemey olla are 
 108 | 15 58 
 169 | 26 | Ior 
 22) 15 57 
 Tr 1s, 59 
 L7O}) 22 87 
 gI| 16 64 
 OS ieee tel iar eur 
 104} 16 63 
 SES neal eon 
 FAC hlis.o.o\ldoue 
 34) 7 27 
 Boilie wis 2 +s 
 | GBiersl Soret 
 TAG | es. 01si|/arevs 
 37.| r2 48 
 95 | 14 a3 
 PIG |e sc eleass 
 TB lisse [ise oi 
 TAS We xcscieanss 
 124] 17 68 
 TAZ) Weve oi lea 01 
 PMN Se Al ORE 
 
58 
 
 ATLAS OF ABSORPTION SPECTRA. 
 
 ALPHABETICAL List OF ABSORBING MEDIA.—Continued. 
 
 
 
 
 
 
 
 ipuency vecliste- yontiaine S4.cde ss 
 WightiGreeni 1. ceicet- areca 
 
 Litmus 
 
 Malachite Greens... ....6.-- v0 
 NMetanil aViellow,s.. oles «crestor 
 Methyl ileohol stn 10.0. 0en 
 Methyl Blue 
 Methyl Ti aaine rere cle-e iris sete 
 Methyl Green 
 Methyl Green OO) «2 orice 
 Methyl Orange III...... 
 Methyl Violet 6 B 
 Mordant Yellow O. 
 Naphthalene Ried fa ees enree- 
 
 B-Naphtholdisulphonic AcidG.... 
 
 Naphthol Green B.. 
 Naphthol Yellow 
 Naphthol) Yellow Seer - sem. =< <- 
 Naphthylamine Brown......... 
 
 aa eC ee © Flee ee © wi 0 ns © 6a 
 
 2 OO we ob 0 4 4 47 © wee 
 es eter ere eee eeee 
 
 po 0 (stwia 600 le see, « 
 
 ») Sie 0.19 se em 
 
 eon ee ast es 
 
 Neodymium Ammonium Nitrate. 
 
 i 
 
 New) Macentag mc citetsinns.c sane occ 
 Nickel: Nitrateicc. Gor. r ees set 
 NickelSSulphateysak enrich o Jone 
 Night Bima aes eutelewe « a ecur cee 
 Nigrosine, soluble.............. 
 p-Nitraniline. (Powder, ‘‘extra.’’).. 
 o-Nitrobenzaldeltydeo..... se = 
 p-Nitrosodimethylaniline......... 
 
 PhenosatraminG.s isc. ..s8 pene 
 iPhloxinesee sects aches peers 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Page| No, | Pl. 
 Boi AA Is 
 35 | 85]. 
 SQM a2 eos 
 34 | 83|/2Z. 
 25 | 32] 10 
 53 | 173| 22 
 pa eS 
 BOE LEON rer = 
 36 | 94| 12 
 30 4) "QB lanes 
 25) 26u £0 
 30 OZ 17. 
 DTN Oi ee.2:s 
 42 ;127) 5 
 21 2) I 
 34 | 80] 3 
 21 ah Sit 
 25 yee 
 2'5, J\\ 33 ieee 
 53 | 174] 25 
 AM ELD Tater sets 
 ZOM TS Tal entacns 
 20) 34| 7 
 35], So7 53 
 54 | 175] 21 
 54 |176] 21 
 BF ie LOla eys-< 
 42 | 126]. 
 2 aa 
 21 agers 
 21 fine 
 22) NEO) oa 
 Asal eA Adonai 
 At |) T2235) 1a 
 AO WT Sa) 5 
 
 
 
 
 
 
 
 
 
 Fig. 
 
 Rhos pie gern cet eteevoistele tis 
 
 eerie] ICRC DCLG iste reievereyeieste , 
 i Saul Poncea 1s (Ol extraarrs er cere 
 841\| Ponceal 2) Gia. a. . ceteris 
 Lae TONGAN Baty 2.0 voici eiotele Rete Raid 
 AGN LE OMCEAIIS IR. (a in. cos letelersie a etoienr ions 
 Br MN Poncea uty RR Bins.» = s.- sels cis aun 
 Gia | MEtesav clever oh) ced 5p s eiey wren ec cas 
 verre GROldostMiMeC ATOMALC.). ele clei 
 47 || Potassium Permanganate....... 
 41 || Praseodymium Ammonium 
 66 Niktratemmoreirenc ot ie.. ess © ole 
 7, | Ouinolineaslusaer inn ses<- 62% 
 20 || Quinoline Yellow Of -jic- 0 <n 
 
 f 2 || Quinoline Yellow, sol. in water.. 
 bes il Redi Violet 5 BR cenee. a cs-:s 4. 
 to || Resorcine (techn. pure)......... 
 42 | Resoreine “Brow sie maee. oer 
 A2 i IWhodamine s.r mretirrsera wii 
 soe || FROSHZUTING: 15). uments eteisie cer 
 90 |; Rose -Bensal haere eet 
 
 | 07 || RosolaneiO™, (seems eee 
 08 || Satranines,)...5 . sere eee ee 
 .2.. |) Sodium, Bichroniatec ari oe 
 -- || Sodium Nitroprussid........... 
 27 || soluble Prussian ime... ~.. see 
 50 || Lhiogene Brown isa:..5 eee 
 81 |) Thiogene: Opamee dn... 2s oes 
 82 1) Tropxolinet@ seen nee 
 cin |) LTOPCOMMeEEO@ came oii 
 - || Lropeoline OOO NO. toss ek 
 Tropaoline OGO-NO, 2.24... en 
 ; = Uranine?) 30-4 dee 2. see nmaeee 
 36 || VeSWVINE). a. of ieaid esioiess seueetetete 
 cite i) MICtORIA VS Ite abe, aroletetes rece 
 Bi}, Water ct. asta stee) «rte. ieee Een 
 60 |) Wool: Black: <n. cnc ae eit 
 
 
 
 Page 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ceeelewee 
 
 eee ele wee 
 
 2 Bi) 6 = ae 
 
 eee elewes 
 
 ser eleecee 
 
 CeCe eee 
 
 No. | Pl. 
 Lig ae 
 | 177 | 22 
 43 ]--+ 
 II 
 HEN (Sey S 
 LY | ha 
 48 | 13 
 51 | 14 
 178 | 20 
 179) 19 
 180 | 26 
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 181 
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 145 
 146 
 147 
 25 
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 26 
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 50| 17 
 
 
 
For convenience in identifying the stronger spark lines, fig 
 
 ‘‘An Introduction to the Study of Spectrum Analysis,’’ by W. M. Watts. 
 
 ATLAS OF ABSORPTION SPECTRA. 
 
 mans, Green & Co., 1904. 
 ‘‘Measurements of the Wave-lengths of Lines of High Refrangibility in the Spectra 
 
 of Elementary Substances.”’ 
 tions of the Royal Society. 
 
 No. W.-l. 
 
 Tie 2024.2 
 3 aga 
 
 2062.8 
 3- 2099.0 
 425 2139.3 
 5: 2144.5 
 6. 2194.7 
 7- 2239-9 
 8. 2265.1 
 Qa 2288.1 
 Oo. | 2300.7 
 Ef 2373.0 
 22321. 2 
 
 13. 2329.3 
 I4. 2502.1 
 I5- 2558.0 
 Boe 2573.1 
 
 2710.1 
 aie ae 
 EO 274857 
 Ig. 2770.9 
 20. 2801.0 
 28. 2837-0 
 22. 2880.9 
 23- 2980.8 
 24. 3007.0 
 25- 3035-9 
 ae le 
 
 3076.0 
 
 Radia- 
 
 tor. 
 
 ZB. 
 
 Zn. 
 Zi. 
 Cd. 
 Ca 
 alk 
 Ga: 
 Cd. 
 Cds 
 Gd: 
 Cue 
 Cd. 
 ZB. 
 Lis. 
 Cd. 
 Air, 
 Zn. 
 Cd: 
 Zn. 
 Zn. 
 (Srsle 
 Cd: 
 Cd: 
 Air. 
 Zn. 
 
 \2n. 
 
 Patt: i 
 Radia- 
 No. w.-l. Rae 
 Parte, ee hite yess (OXGle 
 re ew enc) (Grek: 
 2908 3200.2mn Cd: 
 30. 3282.4..20- 
 3 3302570 eZ. 
 A320. S 1 nse. 
 32): 33365 ir 
 3345-1 
 eee oa 
 34. 3407.7 Cd. 
 35- 3436-9 Air. 
 36. { 3406.3 e Cd. 
 39° 1 3467.8 
 37s 3530. sOun@ Ge 
 3010.7 
 ie 3613.0 
 39. 3682. ~ 
 40. 3712-2 Air. 
 Ao Sy 20.00 Alt: 
 Age 3740.8 Air. 
 3839-3 \ air 
 ue { 3841.7 } 
 44. 3881.9 Air. 
 Asem zO1Gs2) Air. 
 8 . 
 Gis { 3954 \ Air. 
 SL sostiad 
 Hie * elon Ras Air. 
 48. 3995.1 Air. 
 49- 4041.4 Air. 
 
 Hartley and Adeney. 
 1884. 
 
 No. 
 
 50. 
 
 51. 
 52). 
 53> 
 
 54: 
 
 4228.5 
 = 4 4230.7 
 
 W.-l. 
 
 4070.0 
 4072.4 
 4076.1 
 4119-4 
 4132.8 
 4133.8 
 4145-9 
 4151.9 
 4153.6 
 
 4241.9 
 4316.2 
 4318.7 
 4349-5 
 4367-9 
 4415.1 
 ee I 
 4447.2 § 
 4530-1 
 4576.2 
 4001.6 
 4607.3 
 4614.0 
 4021.6 
 4620.0 
 
 4630.7 
 
 ; {ree 
 
 4643.4 
 
 Radia- 
 
 tor. 
 
 Air. 
 Air. 
 \ Air. 
 
 Air. 
 
 is Air. 
 
 \ Air. 
 Air. 
 Air. 
 Air. 
 
 1 Air. 
 Air. 
 
 Cd. oat 
 
 Air. 
 Air. 
 Air. 
 Air. 
 Gd 
 Air. 
 
 \ Air. 
 
 IIg 
 
 ao 
 
 . 99, pl. 25, is given.* 
 The numbers on this positive correspond to those preceding the wave-lengths below. 
 The wave-lengths were derived from the two following sources: 
 
 NI 
 sy 
 ce 
 
 W.-l. 
 
 AV2253 Lis 
 4800.1 Cd. 
 
 4810.7. Zn. 
 
 AGL2.3 (LIK, 
 
 4924.8 Zn. 
 
 5002.7 
 5005-7 
 
 5045.7 Air. 
 5086.1 Cd. 
 
 5116.0 Zn. 
 
 5140.2, Cd. 
 
 5395-00 Cd. 
 5354-4 Cd. 
 5379-3 Cd. 
 5497-4 Cd. 
 5509.0 Zn. 
 Ba4r.8 LD. 
 5602.0 211. 
 5761.8 Cd. 
 5901.6 Cd. 
 
 6014.0 Air. 
 
 6035.0 Zn. 
 6071.8 Zn. 
 
 6144.4 Zn. 
 
 6152.08 /Zm. 
 
 6160.4 Cd. 
 
 6266.6 Cd. 
 
 Air. 
 
 Long- 
 
 From the Philosophical Transac- 
 
 Radia- 
 tor. 
 
 4649.2 Air. 
 
 4680.4 Zn. 
 
 152 
 
 The following table facilitates the finding of the numbers, names, etc., of all the 
 substances which have an absorption spectrum more or less similar to that shown by a 
 selected spectrogram. ‘The third column gives the number of every substance referred 
 in the text to the plate and figure of the preceding columns. 
 
 Plate. 
 
 3 
 
 = 
 
 ml 
 90 0M ONN ADA DUB & W 
 
 = 
 
 *The negative was not a single exposure. 
 
 Fig. 
 
 II 
 I2 
 13 
 14 
 19 
 20 
 
 No. 
 
 33, 63, 79, 116, 118, 135, 140. 
 
 31, 
 
 39, 
 181 
 
 147. 
 
 139. 
 
 10, OF,.105, 125. 
 
 126, 143, 144. 
 126, 138, 144. 
 
 7s 
 38, 
 70. 
 
 59, os 65, 66, 67, JO; 140. 
 
 26, 
 
 57) 
 25, 
 42. 
 
 72; 73) 75+ 
 44. 
 
 9, 29. 
 
 Plate. 
 12 
 12 
 13 
 13 
 14 
 14 
 14 
 14 
 15 
 I5 
 16 
 17 
 18 
 18 
 20 
 
 
 
 + “Doubtful Origin.” 
 
 Fig. 
 
 46 
 47 
 51 
 52 
 53 
 54 
 
 { The subscript 2 denotes the second order of spectrum. 
 
 No. 
 
 83, 84, 85. 
 
 93. 
 49. 
 
 37, 43, 137- 
 
 ~ 133. 
 
 Ler, 124. 
 16, 18, 20, 35, 36. 
 62. 
 
 TiC Lit: 
 
 114. 
 
 To stand reproduction the extreme ultra-violet was ‘‘favored.”’ 
 
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 Re ies a Re oy 
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ABSORPTION SPECTRA. 
 
 62 61 60 59 58 57 56 55 5% 53 B2 51 50 4O 48 AT AE 45 bh WG 42 
 
 SHAE ETAT 
 
 Oo is 39 36 37 66 SB .34 3S 282 .8t .820 .29 .28 27 .26 
 
 
 
 FIG. 1. SEE NO. 1. AMIDONAPHTHOLDISULPHONIC ACID H. 
 FIG. 2. SEE NO. 2. B-NAPHTHOLDISULPHONIC ACID G. 
 
 FIG. 38. SEE NO.-5. P-NITROSODIMETHYLANILINE. 
 FIGRA SEE NOWGe SRESORCINIES 
 ile 0. OREN. 2. 
 
 HELIOTYPE CO., BOSTON. 
 

 
ABSORPTION SPECTRA. PLATE 2. 
 
 62 61 60 58 58 57 50 55 bY 53 52 51 50 49 48 M7 HG 45 be WG AQ 44 WO .39 ai 87 86 35 34 33 82 31 .30 .29 .28 27 a 25 2% .23 .22 21 20 
 inal ul INN issuance wall tutu nt TOSVUUUVATUIQUOLTOLLEHUAAYEROSEH (HAHA hi Mi iii ula 
 
 
 
 FIGs6 
 
 
 
 FIG. 6. SEE NO. 11. PONCEAU 2G. 
 
 FIG. 7. SEE NO. 12. CHRYSOIDINE. 
 
 FIG. 8. SEE NO. 13. CHROMOTROPE 6 B. 
 FIG. 9. SEE NO. 14. AZO COCCINE 2R. 
 
 
 
 HELIOTYPE CO., BOSTON. 
 
pee ae ee 
 
 - +) 
 
 
 
 > 
 
 
 
 
 
ABSORPTION SPECTRA. PLATE 3. 
 
 62 61 66 58 58 57 56 55 54 53 52 51 50 49 4S AT 4G 45 4h 4S AQ 41 40 39 88 37 86 35 34 63 32 31 30 .29 .28 27 .26 .25 .24 
 | Soominitant adit set malls rf sihseeltrntirtil : | 
 used iit PUUURALUUUUAALLRLUTRLLUTRRULAUTREUEEUELAERTGUELURUPUORCPGTCUUTERREEUUUATURGHT CHAO CGPe RE GHOTGORGOH SOHO HANGRRT AGHA | | | | {{| 
 
 
 
 Ph Ah 
 
 
 
 MGs Wile 
 
 
 
 FIG. 13. 
 
 FIG. 10. SEE NO. 80. NAPHTHOL GREEN B. 
 FIG. 11. SEE NO.47. .CLOTH RED 3GA. 
 FIG. 12. SEE NO. 30. CURCUMEINE. 
 
 FIG. 13. SEE NO. 129. COLUMBIA YELLOW. 
 
 HELIOTYPE CO., BOSTON. 
 

 
 
 
ABSORPTION SPECTRA. PLATE 4. 
 
 62 61 60 59 58 57 56 55 53 52 5 5 49 48 LT AC 45 OA 
 
 HATHTHTTAGH TY 
 
 
 
 
 
 FIG. 14. 
 
 
 
 FIG. 14. SEE NO. 119. ALIZARINE RED S. 
 FIG. 15. SEE NO. 107. URANIN 
 FIG, 16; SBE NO. 107. URANINE. 
 
 
 
 m™ 
 
 
 
 HELIOTYPE CO., BOSTON. 
 
ABSORPTION SPECTRA. PLATE 
 
 62 61 60 59 58 57 56 55 hs 58 52 51 50 40 48 47 4G 45 WY 4B 42 41 40 39 38 37 36 35 3% 33 82 31 30 .29 
 
 , i “ a 33 32 3 < 20.28 27 206 25 22 23 22 21 26 
 dunhucnutint MATT bility 
 
 JETT 1 Se Sie es OE 
 
 
 
 FIG. 12: 
 
 aS He jj) 
 
 tf 
 
 r Hh [) 
 
 
 
 FIG te) 
 
 
 
 FIGy 20: 
 
 FIG. 17. SEE NO. 109. EOSINE A L’ALCOOL. 
 FIG. 18. SEE NO. 113. CYANOSINE. 
 
 FIG. 19. SEE NO. 106. ACID ROSAMINE A. 
 FIG. 20. SEE NO. 127. NAPHTHALENE RED. 
 
 WELIOTYPE CO., BOSTON. 
 

 
ABSORPTION SPECTRA. PLATE 6. 
 
 62 61 .60 59 58 57 56 55 54 53 
 
 on 
 iS) 
 t 
 
 51 60 49 48 47 46 45 4h 48 AQ AL 40 39 B88 37 .36 35 B34 33 32 7 0 .2 28 27 16 .25 
 
 Iii ATT 
 
 
 
 
 Al we 
 
 
 
 FiGa22, 
 
 ee Pi 
 
 
 
 7 Te Sy a 
 rere 
 
 
 
 FIG. 24. 
 
 FIG. 21. SEE NO. 46. CLOTH RED O. 
 
 FIG. 22, SEE NO. 74. . BENZOPURPURINE 10 B. 
 FIG. 23. SEE NO.60. CONGO CORINTH G. 
 FIG. 24. SEE NO. 134. ALIZARINE ORANGE. 
 
 HELIOTYPE CO., BOSTON. 
 

 
 re 
 
 
 
ABSORPTION SPECTRA. 
 
 PEATE 7: 
 
 62 61 60 59 58 57 56 55 5’ 5S 52 51 60 4O 48 W7 46 45 Wh WB 4D 41 KO 39 98 87 .36 
 gala Juul | 
 
 
 
 AL ee a 
 
 VP 
 
 
 
 BCR raype 
 
 
 
 FiG. 28; 
 
 FlG. 25. SEE. NO: 45." CBO RED GE: 
 
 FIG. 26. SEE NO. 69. BRILLIANT PURPURINE R. 
 FIG. 27; SEE NO. 84. (RASTBRED' A. 
 
 FIG. 28. SEE NO. 120. ALIZARINE BLUE S. 
 
 HELIOTYPE CO., BOSTON. 
 

 
 
 
ABSORPTION SPECTRA. PLATE 8. 
 
 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 4 12 4 40 39 88 37 .36 a 
 
 
 
 rica Zo: 
 
 
 
 FIG. 30. 
 
 
 
 PiG sit, 
 
 
 
 iG, B2s 
 
 FIG. 29. SEE NO.23. EMIN RED. 
 
 FIG: 30. SEE NO.10. “ORANGE G: 
 
 FIG. 31. SEE NO. 15. BRILLIANT ORANGE G. 
 FIG, o2..5SEE NOS iif] PHOSPniNEs 
 
 
 
 
 
 HELIOTYPE CO., BOSTON. 
 

 
ABSORPTION SPECTRA. PLATE 9. 
 
 i 62 61 60 59 58 57 56 55 5 53 52 51 50 49 AS 47 AG 45 43 43 42 41 40 39 38 37 36 35 34 33 32 31 30 .29 28 27 26 26 24 
 
 17 eT a Le ee eS Te 
 
 
 
 FIG. 33. 
 
 
 
 FIG. 34. 
 
 
 
 FiG.ess; 
 
 
 
 FIG. 36. 
 
 FIG. 88. SEE NO. 56." CONGO ORANGE G: 
 FIG. 34. SEE NO. 141. DIANIL ORANGE G. 
 FIG. 35. SEE NO. 77. CONGO BROWN G. 
 FIG. 36. SEE NO.77. CONGO BROWN G. 
 
 HELIOTYPE CO., BOSTON. 
 

 
ABSORPTION SPECTRA. PLATE 10. 
 
 62 61 60 BO 58 57 56 55 5 53 52 51 50 49 AB MT AG AS U4 4G 42 41 LO 30 G8 37 36 85 34% 33 32 31 
 alti i 
 
 30 .29 .28 27 26 .25 2% 23 22 .21 20 
 
 
 
 
 
 FIG. 38 
 
 il 
 
 i 
 
 
 
 i | i 
 
 PUGinoO. 
 
 es Se | E 
 aed | 
 
 
 
 FIG. 40. 
 
 FIG. 37. SEE NO. 81. CURCUMINE S 
 
 FIG. 88. SEE NO. 41. RESORCINE BROWN 
 FIG. 39. SEE NOEs: AURANTIA. 
 
 FIG. 40, SEE NO, 32. METANIE YEREOW- 
 
 HELIOTYPE CO., BOSTON. 
 

 
 
 
 
 
 ‘- 
 
 
 
ABSORPTION SPECTRA. PLATE 11 
 
 62 61 60 59 58 .57 56 55 54 56 52 61 50 40 AS 47 46 45 4h 4S 42 41 40 «89 38 37 £86 25 34 33 32 31 30 .29 .28 27 .26 25 24 
 halla wuteulinati , 
 
 
 
 FIG. 42. 
 
 
 
 FIG. 44. 
 
 SEE NO. 28: METMYL ORANGE III 
 FG, 42. Sec NO. 7. NAPHTHOL YELLOW. 
 SEE NO. 82. AURAMINE O. 
 FIG. 44. SEE NO.131. QUINOLINE YELLOW O. 
 
 
 
 
 
 
 
 
 
 HELIOTYPE CO., BOSTON. 
 

 
ABSORPTION SPECTRA. 
 
 om 
 
 PRAT Es. 
 
 62 61 60 59 58 57 56 55 Be 5S 52 51 50 49 AS 47 A 
 
 
 
 FIG. 46. 
 
 
 
 FIG. 47. 
 
 
 
 PCE iw Hi ie cam’ 
 
 
 
 FIG. 45. SEE NO. 136. AUROPHOSPHINE 4 G. 
 FIG. 46. SEE NO. 86. ACID GREEN, CONC’. 
 FIG. 47. SEE NO. 94. METHYL GREEN. 
 
 FIG. 48. SEENO. 87. FUCHSINE. 
 
 
 
 HELIOTYPE CO., BOSTON 
 

 
ABSORPTION SPECTRA. PISA ates 
 
 62 61 60 59 58 57 56 55 BL 58 52 51 50 49 48 47 46 AS 4 43 42 41 40 39 88 87 86 35 3% B38 32 .31 .80 .29 28 27 26 25 24 23 22 21 20 
 
 atta anti uettiiatudaeeelataad 
 
 
 
 FIG, 49. 
 
 5 A 
 
 
 
 Pig oe: 
 
 FIG. 49. SEE NO. 100. CORALLINE RED. 
 FIG, 50. SEE NO..88. NEW MAGENTA. 
 
 FIG. 51. SEE NO. 48. PONCEAU 4R B. 
 FIG. 52. SEE INO. 21. EOSAMINE 6B. 
 
 HELIOTYPE CO., BOSTON. 
 

 
 
 
 
 
 
 
ABSORPTION SPECTRA. PLATE 
 
 62 61 60 59 58 57 56 55 5% 53 52 51 50 49 48 47 AG AB Yh 4B 4D 41 40 .B9 .B8 .B7 .B6 B85 3% B23 82 .31 .B0 .29 .28 27 .26 .25 2% .23 .22 
 
 
 
 FiG. Os. obce NO. 96. UGH SINE Ss: 
 
 FIG. 54. SEE NO. 122. PHENOSAFRANINE. 
 FIGs56; SEE-NO Wis. SPONCEAUSS  R: 
 PIG, 06. (SEE NOU 51. -PONCEAU 6 RB: 
 
 HELIOTYPE CO., BOSTON 
 

 
ABSORPTION SPECTRA. PLATE 1 
 
 62 61 60 59 5S 57 56 55 5% 5G 52 51 50 49 48 47 4G 45 tb) 
 i 
 
 daniel 
 uli 
 
 
 
 
 
 FIG. 60. 
 
 FIGr67. SEE NO. 225 (ERNKAB. 
 
 BIGs 58. SEE NO. 706, EOSINE, YELEOWiISr: 
 PIGLSo, SEE NOS HZ. ERY GER@SINE. 
 FIG.6O. SEE NOD TiS. PHEOKINIE: 
 
 
 
 HELIOTYPE CO., BOSTON. 
 

 
 ao 
 
 ‘a 
 - 
 
 
 

 
 62 .61 60 59 58 57 56 55 5% 53 52 51 50 .49 48 AT AG AS Hh MO 42 AL LO 
 Hees rat | i | 
 
 86 35 .34 33 382 31 .80 .29 .28 27 26 .25 2% 23 22 .21 
 adalat utr undue / 
 
 ih mn 
 
 bi ons 
 
 
 
 FIG. 61; 
 
 
 
 FIG. 62. 
 
 
 
 RIG. 63: 
 
 
 
 FIG. 64. 
 
 FIG. 61. SEE NO. 68. DIAMINE RED 3B. 
 PiG. 62. SEE .NO,go. REO VOLES Rese 
 FIG. 68. SEE NO. 104. FAST ACID VIOLET B&B. 
 Fig. 64. SEE NO: Si.) Era VIOLET. 
 
 
 
 HELIOTYPE CO., BOSTON. 
 

 
ABSORPTION SPECTRA. PLATE 
 
 8 G2 61 60 59 5S 57 56 85 5%° 53 B2 1 60 40 AS 47 AG AB OY AB 42 41 HO 29 B88 37 36 BB BS 339 32 31 .B0 .29 28 27 26 25 24 
 
 Feng 
 
 : 
 
 
 
 PIG wey. 
 Mf SSMS es ae ai 
 
 
 
 FIG. 68. 
 
 
 
 FIG. 65. SEE NO. 103. RHODAMINE B. 
 
 FIG. 66. SEE NO. 925" METRY VIOEET Gs: 
 FIG. 67. SEE NO. 50. WOOL BLACK. 
 
 FIG. 68; SEE NO. 124. HELIOTROPE-2B. 
 
 HELIOTYPE CO., BOSTON. 
 

 
 
 
 oo : = 
 r 
 yi / 
 in 
 » 
 * 
 . 
 mn % 
 Jan) 
 2 
 * 
 « 
 « 
 de 
 — 
 
 
 
G0 
 
 ABSORPTION SPECTRA. PLATE 1 
 
 psa SO 58 58 57 56 BS St 53 52 51 50 49 AB AT AG AB BA 4G 42 41 40 30 G8 37 26 35 3% 33 32 31 30 .20 28 27 .26 25 2% .23 22 21 20 
 funn oan i nf 
 
 1 SR i a 
 
 
 
 FIG. 69. 
 
 
 
 FIG. 69. SEE NO. 89. DAHLIA. 
 
 FIG. 70. SEE NO. 102. VICTORIA BLUE 4R. 
 FIG. 71, SEE NO. 99. ‘CHINA BLUE. 
 FIG. Gee NO} sALSAL| BEUE 6B: 
 
 HELIOTYPE CO., BOSTON. 
 
7 
 
 Fo 
 
 
 
ABSORPTION SPECTRA. 
 
 62 61 60 58 58 57 56 55 5Y 53 52 51 50 49 48 AT 46 4S Wh 4S 4D AL 40 39 38 37 86 35 34 33 32 3 
 | btn etal bsaathtih facie | | 
 
 PLT 
 
 See NGS 
 SEE WING: 
 SEE NO. 
 oEE NO; 
 
 S08 I il 
 
 FiG. «76. 
 
 149. AESCULINE. 
 
 179. POTASSIUM PERMANGANATE. 
 179. POTASSIUM PERMANGANATE. 
 182. SODIUM NITROPRUSSID. 
 
 
 
 HELIOTYPE CO., BOSTON. 
 
 
 

 
ABSORPTION SPECTRA. 
 
 62 61 60 59 58 57 56 55 5% 53 52 51 50 40 48 M7 4G 45 Wh 4B 42 WA 40 89 .B8 .B7 86 35 3% 83 82 31 .80 .29 28 27 .26 25 24 23 22 21 21 
 anal uta 
 
 a ee ee re ae ee 
 
 y Ir! 
 
 
 
 FIGi 77. 
 
 Ee ay 
 
 
 
 Fics 
 
 
 
 FIG. 77. SEE NO.N68; COPPER CHEORIDE: 
 FiG. 78 SEEINO. 156. COBALT GHEORIDE: 
 
 
 
 
 
 Mm 
 
 FIG: 79: SEE NO. 155. CHROMIUM CHLORIDE. 
 FIG. 80. SEE NO. 178. POTASSIUM CHROMATE. 
 
 HELIOTYPE CO., BOSTON, 
 

 
ABSORPTION SPECTRA. PLATE 2h. 
 
 61 60 .59 58 on 56 aS 5 53 
 
 .50 
 ‘ln alt ivi mn didi abtub idole iti 
 | 1 a a 
 
 | 
 
 41 40 39 88 37 36 35 34 33 a ‘B31 80 .29 .28 27 .26 .25 .2% .23 .22 21 .20 
 
 | 
 MTT 
 HVNTNNUANTUATO 
 
 
 
 THSUTMATUUATHLUUUL 
 
 
 
 {Hit 
 
 
 
 FAG ee 
 
 
 
 PGs ee. 
 
 
 
 FIG. 88. 
 
 
 
 FIG, 84. 
 
 
 
 mC hee): 
 
 FIG..81, SEE NO: 175. NICKEL NITRATE. 
 FIG, 82. SEE NO. 176. NICKEL SULPHATE. 
 PIG. 83. SEE NOMI72. JIM ESS BiRUEs 
 FiG. 84. SEE NO; 172, EMPMUS, RED; 
 
 FIG; 85. SEE NO. 161. COBALT GLASS, 
 
 
 
 HELIOTYPE CO., BOSTON. 
 

 
ABSORPTION SPECTRA. 
 
 62 61 60 i 58 57 56 55 54 53 52 S51 50 40 AS AT 46 4S 44 18 42 41 40 39 88 37 86 35 3% 33 82 31 30 .29 28 27 26 25 2% 23 22 21 
 hee Muti inurl ICRA nh tt | | | mi alfa | 
 
 
 
 FIG, 88. 
 
 
 
 FIG. 86. 
 FiG. 875 
 FIG. 88. 
 FIG. 89. 
 
 SBE INOW it: 
 SEE NO. 148. 
 SEE INO. 50: 
 SEE NO. 154, 
 
 PICRIC ACID. 
 
 ACETONE, ETHYL ALCOMGE Eire; 
 ALUMINIUM CHLORIDE, ETC. 
 CARBORUNDUM AND DIAMOND. 
 
 HELIOTYPE CO., BOSTON. 
 

 
ABSORPTION SPECTRA. 
 
 ' 61 60 .B9 58 57 56 5B 5B 53 52 51 50 4O AS 47 46 45 44 43 42 41 40 39 88 B37 BE 35 .3B4 33 B82 B31 .30 29 28 27 .26 25 24 .23 22 21 .20 
 rey | 
 nui i hs 
 
 Wye Why | 
 WTA 
 
 
 
 
 
 melanie 
 
 
 
 
 
 FIG. 90. SEE NO, 158. COBALT CHLORIDE IN SOLVENTS. 
 FIG. 91. SEE ONO. 165. COPPER CHLORIDE IN SOLVENTS, 
 FIG. 92. SEE NO. 164. CHLORIDES OF CALCIUM AND COPPER. 
 
 
 
 HELIOTYPE CO., BOSTON. 
 

 
ABSORPTION SPECTRA. 
 
 “- 61 60 59 58 .57 56 55 5 53 52 51 50 49 48 7 46 AB 4h 4B 42 41 40 39 .B8 37 86 .B5 B34 B83 B2 .B1 .80 .29 .28 27 .26 25 24% 26 22 21 2 
 Tah Hear hve t ear | on 
 ansuntvivdtveit li MMT | | | 
 
 
 
 
 
 
 
 
 
 
 
 
 
 FiGs SS. 
 
 
 
 FIG. 93. SEE NO. 165. COPPER CHLORIDE IN ACETONE. 
 FIG. 94. SEE NO. 158. COBALT CHLORIDE IN ACETONE. 
 FIG. 95. SEE NO. 157. CHLORIDES OF ALUMINIUM AND COBALT. 
 
 HELIOTYPE CO., BOSTON. 
 

 
 ~w 
 
 
 
ABSORPTION SPECTRA. PLATE 
 
 32 61 60 59 58 57 56 55 5’ 53 52 51 50 49 48 wT KO 45 bd 4G AD AL 40 39 38 37 86 35 384 33 82 31 .380 .29 .28 27 26 25 24 
 
 a 2 ~ SSE EES soe 
 
 ; cL Ped aaa 
 ak i 
 _ A NE ARE AT I spe tam 
 
 
 
 
 FIG. 97. 
 
 
 
 
 
 FIG. 96. SEE NO. 174. NEODYMIUM AMMONIUM NITRATE. 
 FIG. 97. SEE NO. 174. NEODYMIUM AMMONIUM NITRATE. 
 
 FIG. 
 Fit 
 
 SEE NO. 174. NEODYMIUM AMMONIUM NITRATE. 
 Sat PAGE M69) 
 
 
 
 cc «Cc 
 see 
 
 HELIOTYPE CO., BOSTON. 
 

 
ABSORPTION SPECTRA. 
 
 PLATE 26 
 
 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 AT 46 48 paced 43 42 dat 40 39 .38 37 36 35 .34 .33 82 31 .80 .29 .28 27 .26 .25 24% 23 .22 .21 .20 
 | Ney rat | | +a | De dives licatt statin | | f hy 
 width i 
 
 WH 
 
 TA 
 
 
 
 FIG. 100. 
 
 
 
 FIG. 100. SEE NO. 180. PRASEODYMIUM AMMONIUM NITRATE. 
 FIG. 101. SEE NO. 169. ERBIUM CHLORIDE. 
 FIG. 102. SEE PAGES 5 amd 20 
 
 
 
 HELIOTYPE CO., BOSTON. 
 

 

 

 
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 hoe