402 Progress in Science: [July, 



consisting daily of 20 grms. of bread, 10 grms. of fresh butter, and 10 grms. of 

 sugar ; in the other case, 20 grms. of cacao, 10 grms. of sugar, and an 

 infusion of 20 grms. of well-roasted coffee. From these experiments the 

 author draws conclusions leading him to consider coffee and cacao as simply- 

 preventing de-nutrition. This view has been objected to by MM. Payen, 

 Dumas, and Chevreul. As regards cacao (commonly, but erroneously, in this 

 country named cocoa), there can be no doubt that, containing as it does from 

 17 to 20 per cent of albuminous matter, with from 10 to 12 per cent of starch, 

 from 40 to 50 per cent of fat, and among its mineral matter phosphates, 

 it is food. M. Chevreul very properly observes, among other matters, the 

 existence of idiosyncracy, and its influence on the individual tastes, and hence 

 also more or less on the action of various alimentary substances, pointing out 

 that he himself has, from his earliest years, an invincible repugnance against 

 wine, milk, fish, and various vegetables, none of which he ever partakes 

 of, but for all that it would, of course, be absurd to deny the nutritive proper- 

 ties and value of these substances. 



The occurrence of the metal manganese in the mineral kingdom has been a 

 matter of discussion and some little doubt. Dr. J. E. De Vry states that, 

 while studying in Germany, thirty years ago, he collected beech-nuts in 

 the vicinity of Giessen, and found the ashes of these nuts to contain a rather 

 large percentage of manganese, which was readily explained by the fact of that 

 mineral being present in that locality rather abundantly. In 1847, being at the 

 meeting of the British Association at Oxford, the author gathered some 

 unripe beech-nuts in Blenheim Park, which, on being afterwards tested, were 

 found to contain a relatively large amount of manganese, although grown in a 

 very different soil. A third analysis of the ashes of beech-nuts, collected in 

 the wood of the Hague, confirmed the same fact. 



Dr. A. Vogel has described a simple experiment to illustrate the action 

 of dilute sulphuric acid upon starch. Since nearly all kinds of writing paper 

 are nowadays so very largely sized with starch that they are coloured blue by 

 a dilute solution of iodine, the following experiment may be made to 

 illustrate visibly the change which starch undergoes when acted upon by 

 dilute sulphuric acid, for which purpose writing or other figures are traced on 

 the paper with very dilute sulphuric acid, and a gentle heat applied, care being 

 taken not to char the paper. When next a dilute solution of iodine is painted 

 over this paper, the portion acted upon by the dilute acid remains white, while 

 the rest becomes blue ; but since, in course of time, this blue colour disappears 

 altogether, . the same piece of paper may be repeatedly used for this experi- 

 ment. 



The true constitution of artificial ultramarine has long been a matter 

 of doubt. Dr. W. Stein has written a long essay on the mode of combination 

 in which the sulphur is present in it. The author states that his aim is 

 to prove that blue ultramarine contains sulphurous, not hyposulphurous acid, 

 which former, however, is not an essential constituent ; and further, that 

 ultramarine contains only sulphuret of aluminium, there being no sulphuret of 

 sodium at all. The conclusions drawn by the author from his experiments 

 are — Ultramarine consists mainly of a white mass, through which and with 

 which black sulphuret of aluminium is most intimately and molecularly incor- 

 porated ; the blue colour of ultramarine is, therefore, not due to its chemical 

 composition, but to the optical relation of its component substances. The 

 essay winds up with some observations on white and green ultramarine ; 

 the latter contains less soda than the blue-coloured pigment, and that, 

 again, less soda than the white pigment. The quantity of sulphur contained 

 in blue-coloured ultramarine is less than that contained in green-coloured 

 ultramarine. 



The examination of some ancient silver ornaments has led Professor 

 Church to a curious result, which may prove of interest to some of our 

 readers. The silver objects referred to were obtained lately by General de Cesnola 

 in the Island of Cyprus. He opened several hundreds of tombs, specially at 

 Dali, the site of the ancient city of Idalium, and obtained large quantities 



