94 



NATURE 



[May 26, 1892 



be made were shown. The principle of the measurements 

 depends on the selective absorption of the constituents of normal 

 white light by coloured glasses (red, yellow, and blue). The 

 depths of tint of the glasses are carefully graduated to give 

 absorptions in numerical proportions. For example, two equal 

 glasses, each called one-unit red, give the same absorption as a 

 two-unit red, and so on. The units of red, yellow, and blue 

 are so chosen that a combination of one of each absorb white 

 light without colouring the transmitted light. Such a combina- 

 tion is called a "neutral tint unit." By the use of successive 

 neutral tint units, white light can be gradually absorbed without 

 showing traces of colour, and the number of such units required 

 to produce complete absorption is taken as a measure of the 

 intensity or luminosity of the white light. Methods of represent- 

 ing colours by circles and charts were fully dealt with, and the in- 

 fluence of time of observation on the penetrability of different 

 colours was illustrated by diagrams. The results of 151 experi- 

 ments on colour mixture were explained, and represented 

 diagrammatically. After the reading of the paper the methods 

 used for colour matching and measurement were shown by 

 Mr. and Miss Lovibond. — Mr. R. W. Paul exhibited his im- 

 proved form of Wheatstone bridge, arranged to occupy the same 

 space, and fulfil the same conditions, as the well-known Post 

 Office pattern. 



Chemical Society, April 21.— Prof. A. Crum Brown, 

 F. R. S., President, in the chair. — The following paper was 

 read : — Masrite, a new Egyptian mineral, and the possible 

 occurrence of a new element therein, by H. D. Richmond and 

 Hussein Off. Masrite is the name assigned by the authors to a 

 variety of fibrous alum obtained in Egypt by S. E. Johnson 

 Pasha. It contains from i to nearly 4 per cent, of cobalt. 

 This being the first occasion on which cobalt has been met with 

 in Egypt, the authors were led to inquire whether the blue 

 colour used in the paintings on Egyptian monuments contained 

 that element. The samples obtained, however, owed their colour 

 to compounds of copper and iron. The mineral is principally 

 interesting on account of the presence in it of a minute quantity 

 of a substance, the properties of which appear to be unlike those 

 of any known element, which the authors provisionally term 

 masrium, from the Arabic name for Egypt. From an analysis 

 of the oxalate, on the assumption that it is a bivalent element, 

 the atomic weight of masrium is calculated to be 228. The 

 authors point out that there is a vacant place in the glucinum- 

 . calcium group of the periodic system for an element having the 

 atomic weight 225. In many of its properties masrium resembles 

 glucinum, and the oxalate is analogous to that of calcium. 

 Masrite has the composition 



(Al,Fe)203, (Ms,Mn,Co,Fe)0, 4SO3, 20OH2. 



Mays. — Prof. A. Crum Brown, F.R.S., President, in the 

 chair. — An extract was read from a letter to Sir H. E. Roscoe, 

 written by Prof. Kiihne, of Heidelberg, at the request of Prof. 

 Bunsen, expressing his thanks for the address presented to him 

 by the Chemical Society. — The following papers were read : — 

 The existence of two acetaldoximes, by W. R. Dunstan and T. 

 S. Dymond. Acetaldoxime, CH3 . CH : NOH, has hitherto 

 been regarded as a liquid capable of existing in only one form, 

 attempts to obtain evidence of the existence of an isomeride 

 having failed ; the authors, however, find that it can be 

 crystallized by cooling. The crystals so obtained are often 

 several inches in length, and melt at 46° '5. On heating them to 

 100°- 1 50° no decomposition occurs, and the substance boils con- 

 stantly at II4°"5. If this heated liquid be now cooled, it does 

 not crystallize until nearly 35" below the melting-point of the 

 original substance, and the crystals so obtained become liquid at 

 ordinary temperatures. Many similar observations have been 

 made, and it has been invariably found that on heating the 

 aldoxime the freezing-point is lowered to a greater or less extent. 

 Evidence has in this way been accumulated, showing that a 

 change in the constitution of acetaldoxime occurs when it is 

 heated, the original substance, melting at 46°"5, being gradually 

 converted into a new modification, which melts at 12°. It is 

 noteworthy that the acetaldoxime melting at 12° is slowly recon- 

 verted into that melting at 46° •£ on standing at ordinary tem- 

 peratures. The authors term the substance melting at 46°'5 

 o acetaldoxime, that melting at 12° being named j3-acetaldoxime. 

 — Sulphonic acids derived from anisoils (No. i.), by G. T. 

 Moody. The author finds that contrary to the statement of 

 Kekule, and of Opl and Lippmann, anisoil and phenetoil afford 

 only parasulphonic acids on sulphonation. Carefully purified 



NO. II 78, VOL. 46] 



anisoil was dissolved in concentrated sulphuric acid, and the 

 product poured into water, when part of the anisoil was liberated, 

 showing that as in the case of phenol an intermediate compound 

 is formed before the sulphonic acid. The anisoil thus set free 

 was treated with strong sulphuric acid at 80°, when complete 

 sulphonation occurred. The solution yields a well-defined 

 calcium salt ; no indications of the presence of an isomeride were 

 found. The calcium, potassium, and sodium salts of the anisoil 

 parasulphonic acid obtained in this way are described, together 

 with the sulphochloride and sulphonamide. Pure phenetoil simi- 

 larly is shown to yield only the parasulphonic acid. The products 

 of sulphonation, either with sulphuric acid or with chlorosulphonic 

 acid, are in both cases the same, only one sulphonic acid 

 resulting. — The formation of trithionate by the action of iodine 

 on a mixture of sulphite and thiosulphate, by W. Spring. In 

 his paper on the investigation of the change proceeding in an 

 acidified solution of sodium thiosulphate, Colefax credits the 

 author with having slated that trithionate of sodium is produced 

 when iodine acts on a mixture of sodium sulphite and 

 thiosulphate, and further denies that this is the case. The 

 author used potassium salts, and not sodium salts, but, owing to 

 an error in the abstract of Spring's original paper, Colefax was 

 led to believe that sodium salts were used. The difference in 

 the behaviour of the potassium and sodium salts is very striking, 

 and arises from the greater instability of the sodium polythionates 

 already pointed out by the author. Another difference between 

 the two sets of experiments is found in the employment by 

 Colefax of a larger proportion of iodine than that used by the 

 author. The equation 



K2SO3 + K2S2O3 4- lo = K2S3O6 + 2 KI 



requires less iodine than would be necessary to oxidize the 

 sulphite to sulphate, and the hyposulphite to tetrathionate of 

 sodium. The author does not, however, contend that the 

 formation of trithionate takes place in accordance with the 

 equation 



Na2S203 + NaoSOg + Ij = Na2S306 + 2NaI. 



He is convinced that sulphites have the property of desulphuris- 

 ing the tetrathionates, so as to convert them into trithionates. 

 It would hence be more consistent to admit that the sodium 

 sulphite which owes its existence to the employment of a 

 reduced quantity of iodine decomposes the small quantity of 

 sodium tetrathionate produced in the first instance, thus, 



Na2S406 H- Na2S03 = N£2S306 + Na2S203. 



The statement erroneously ascribed by Colefax to the author 

 seems, in consequence, to be really correct. It is, however, 

 indispensable that the experiments should be performed under 

 exactly the same conditions as those employed in the work 

 on the potassium salts. — The determination of the temperature 

 of steam arising from boiling salt solutions, by J. Sakurai. The 

 evidence now on record as to the temperature of the steam 

 arising from boiling salt solutions is exceedingly unsatisfactory 

 and inconsistent. Such being the case, the author has devised 

 a method for accurately measuring this temperature, and finds 

 that the temperature of the steam escaping from a boiling salt 

 solution is the same as that of the solution. The conditions for 

 success are : — ( i ) The thermometer used must be kept from 

 contact even- with the smallest drops of the solution thrown up by 

 ebullition. (2) The effect of cooling of the thermometer by 

 radiation must be rendered insignificant in proportion to the heat- 

 ing up by the steam. This condition is readily fulfilled by the 

 expedient of combining the introduction of steam from without 

 with the ebullition by the lamp. (3) The walls of the chamber 

 surrounding the thermometer must be sufficiently protected from 

 external cooling, and yet, at the same time, must not be heated 

 to the temperature of the steam. This is effected by jacketing 

 the steam chamber with the vapour evolved from dilute acetic 

 acid boiling at about 2° lower than the salt solution. The agree- 

 ment between the numbers representing the temperature of the 

 steam and that of the boiling salt solution is good. — Note on an 

 observation by Gerlach of the boiling-point of a solution of 

 Glauber's salt, by J. Sakurai. Some years ago Gerlach stated 

 that the steam escaping from a boiling solution of Glauber's salt 

 containing a crystalline magma of the anhydrous salt indicates a 

 temperature of 100°, whilst the liquid is boiling at 82° or even 

 72°. The author finds that this is hardly true, for it is only a 

 wet mass of sodium sulphate crystals that is heated. The steam, 

 consequently, does not arise uniformly from the heated mass, but 



