CHEMISTRY. 



87 



and fixed it at a degree which would require 

 the atomic weight to be increased by one half, 

 or to 13 '6, to make it conform to the received 

 atomic heat. Chemists were not inclined to 

 change the determination of the atomic weight 

 of the metal without further evidence; for if 

 it were fixed at 9'1, beryllium, uniting with 

 oxygen as a protoxide, would readily find its 

 place in the magnesium group ; whereas, if its 

 atomic weight were\13'2, its oxide would be a 

 sesquioxide, and its place would be in the alu- 

 minum group. No place, however, could be 

 found under Mendelejeff's classification of the 

 elements according to their atomic weights for 

 a metal having the properties of beryllium and 

 the atomic weight and combining proportions 

 assigned to it by this determination ; and the 

 value of Mendelejeff's classification is too great 

 to make a departure from it expedient except 

 on the most cogent evidence. Nilson and Pet- 

 terson have recently repeated the determina- 

 tion of the specific heat of beryllium at differ- 

 ent intervals from zero to 300, and have again 

 calculated the atomic weight at 13-6. Lothar 

 Mayer has, however, since gone over their 

 numbers, calculating the specific heat of beryl- 

 lium at various temperatures, and has reached 

 results which agree best with the former deter- 

 mination of 9*1. It appears from the experi- 

 ments that while the specific heat of this ele- 

 ment rises as the temperature increases, the 

 value of the increase of specific .heat for one 

 degree diminishes. In this respect, beryllium 

 resembles boron, carbon, and silicon, while for 

 other elements whose specific heat increases 

 with increase of temperature the value of the 

 increase for one degree also increases. 



Professor J. P. Cooke has continued his ex- 

 aminations, begun in 1878, to determine the 

 atomic weight of antimony. His former experi- 

 ments left a slight margin of variation ; his later 

 ones gave almost absolutely uniform results. 

 The mean result of five experiments in the de- 

 composition of the bromide of antimony with 

 silver indicated that bromine was present in the 

 former substance in the proportion of 66'6651 

 per cent. ; corrections of two of the experi- 

 ments by a process which made them in effect 

 distinct determinations, although performed 

 with the same materials, gave the proportion 

 of bromine as 66'666 per cent. These results, 

 taking the atomic weight of silver as established 

 at 108 and that of bromine at 80, give the 

 atomic weight of antimony as 120. 



The earth from the mineral euxenite, which 

 was formerly called erbia and was supposed to 

 be the oxide of a single element, has been found 

 by Nilson to contain not less than seven differ- 

 ent oxides. Two of these oxides, ytterbia and 

 scandia, were subjected by him to special exam- 

 inations. Ytterbia was separated from the 

 other earths, after performing sixty-eight de- 

 compositions. The atomic weight of the metal 

 ytterbium was then determined from the mean 

 result of the analysis of seven fractions of the 

 sulphate to be 173-01. 



Nilson separated scandium from ytterbium, 

 with which it is found associated, by forming a 

 double sulphate of scandia and potassa, whence 

 the scandia was extracted under the form of a 

 nitrate. This salt, having been further purified 

 of ytterbia, was examined in four fractions, 

 from the mean result of the analyses of which 

 the atomic weight of scandia was determined 

 at 44'03. This determination agrees exactly 

 with the atomic weight which Mendelejeff de- 

 rives from his periodic law for ekaber, with 

 the predicted properties of which scandium 

 oxide, ScaOs, coincides. 



Damage to Bookbindings by Gas- Combustion 

 Products. Professor William Ripley Nichols 

 has reported on the results of investigations 

 he has made with reference to the correct- 

 ness of the theory which ascribes deteriora- 

 tion in the bindings of books in libraries to 

 the action of sulphuric acid generated by burn- 

 ing coal-gas. Having examined a large number 

 of samples of leather in every stage of decay, 

 he found that morocco was but little affected, 

 common sheep binding was attacked, and rus- 

 sia leather and calf were badly acted upon. 

 An acid taste and an acid reaction were ob- 

 served that were more marked in proportion 

 as the leather was decayed, and sulphuric acid 

 was found in the extract made from the leather 

 with water, in a similarly increasing propor- 

 tion. Ammonia was also present, in about 

 such a proportion as in combination with the 

 sulphur would constitute the acid sulphate of 

 ammonia. Samples of fresh leather gave ex- 

 tracts only slightly acid, not enough so to 

 affect the taste, and contained only a minute 

 amount of sulphuric acid in combination. Sam- 

 ples of russia leather and sheep of good quality 

 yielded from less than a quarter to less than a 

 half of one per cent, of acid, and less than a 

 quarter of one per cent, of ammonia. A sam- 

 ple of well-worn but not decayed sheep taken 

 from a Bible more than sixty years old. which 

 had never been exposed to gas, gave 1'42 per 

 cent, of sulphuric acid. Other samples, of 

 very rotten russia, and of scrapings from a 

 number of books, gave from eight to ten per 

 cent, of sulphuric acid, combined with ammo- 

 nia. A quantity of rotten leather was carefully 

 extracted with water, and crystals of sulphate 

 of ammonia were obtained from it. Professor 

 Nichols believes that in the face of these facts 

 it is difficult to escape the conclusion that bind- 

 ings absorb sulphuric ncid when exposed to 

 the products of the combustion of illuminating 

 gas, as no other condition to which books are 

 commonly exposed can account so well for the 

 large proportion of acid which was found. 

 To the objection that sulphurous (not sulphuric) 

 acid is the general product of the combustion of 

 sulphur compounds, Professor Nichols answers 

 that his analysis of the products of the burning 

 of gas have brought out sulphates with no evi- 

 dence of the presence of sulphites. He admits, 

 however, that the disintegration of the leather 

 may precede the absorption of sulphuric acid, 



