1871-] Engineering. 543 



Kalaite 2A1 2 3 .P 2 5 + 5H 2 0. 



Caeruleolactine .. 3Al 2 3 .2P 2 5 + ioH 2 0. 

 Wavellite .. .. 3 Al 2 3 .2P 2 5 + i2H 2 0. 



Dr. Petersen has also analysed the mineral described by Breithaupt as 

 Variscite, and finds it to contain A1 2 3 .P 2 5 + 4H 2 0. It appears to be closely 

 related to Damour's Callais — a material which is found, worked into orna- 

 mental objects, in the old Celtic graves of Brittany. 



The New Zealand nephrite or jade — a substance so largely used by the 

 Maories for purposes of ornament — has frequently been subjected to scientific 

 examination, but often with discordant results. Dr. Kenngott has availed 

 himself of some specimens recently obtained from a large block sent to 

 Germany, and his microscopic and chemical examination leads him to con- 

 clude that the different forms of New Zealand jade are micro-crystalline or 

 imperfectly-slaty varieties of grammatite. 



A new fluoride from Arksutfiord, in Greenland — the celebrated locality 

 for cryolite — has been described by Professor G. J. Brush under the name 

 of Ralstonite. It is essentially a hydric aluminium fluoride, crystallising in 

 colourless or white octahedra, and somewhat resembling in its general characters 

 the rare Cornish mineral — fluellite. 



Monzonite is the name which Von Kobell has applied to a new mineral from 

 Mount Monzoni, in the Fassa Valley, Tyrol. It occurs in compact masses, 

 of a pale green colour, somewhat resembling a green hornstone, but is readily 

 fusible. > Analysis shows it to be a new silicate of alumina, protoxide of iron, 

 lime, magnesia, soda, &c, referable to the formula 2(3R0.2Si0 3 ) + 2Al 2 3 .3Si0 3 . 



At the celebrated salt-mines near Stassfurt, in Prussian Saxony, crystals of 

 boraeite have recently been found in tetrahedral forms. 



An analysis of allophane from the oolites of Northampton has been 

 published by Mr. Herman in the "Quarterly Journal of the Geological Society." 

 Mr. D. Forbes in examining this mineral has detected phosphoric acid. 



Professor Rammelsberg publishes an analysis of the meteoric stone of 

 Chantonny ; together with short memoirs on the sulphide of iron occurring 

 in meteorites, and on the composition of Lievrite. 



Papers by Professor Maskelyne on Dufrenite and a new mineral from 

 Cornwall, and on the localities of Dioptase, were read before the Chemical 

 Section of the British Association. In compliment to Professor Andrews, 

 the President of the Section, the name of Andrewsite has been bestowed upon 

 the new Cornish species. It occurs in globular forms, or in discs with a radiate 

 structure, and presents a bluish-green colour. Its sp. gr. is 3*475> an d its 

 composition may be thus formulated: — 3-j Fe 2 P 2 0s + Fe 2 H606 ^ + CuP 2 Os. 

 As the only locality hitherto recorded for Dioptase has been the copper mine 

 of Altyn-Tubeh, in the Kirghese Steppes, it is interesting to learn that Pro- 

 fessor Maskelyne has found this rare species in old specimens from several 

 localities in Chili.* 



ENGINEERING— CIVIL AND MECHANICAL. 

 Guns and Armour. — Since the first introduction of heavy iron plating for the 

 protection of our ships and forts, a continuous rivalry has been going on 

 between guns and armour-plating. The experiments undertaken when a new 

 gun was introduced, or a new kind of armour-plating invented, resulting at 

 one time in favour of the former, and at another time in favour of the latter. 

 At present guns have achieved the last, victory over a new target designed by 

 the War Office authorities. It is uncertain, however, at present, whether this 

 success is to be attributed solely to the superiority of the guns and projectiles, 

 or to the inferiority of the target ; and referring to the great success achieved 

 by the Milwall shield, in July, 1868 — in which the armour-plates were backed 

 with Mr. Hughes's 7-inch hollow stringers, placed horizontally, whilst the 

 rear skin-plates were strengthened by hollow stringers placed vertically — it is 

 just possible that the present victory of the guns may be due more to the 

 inferiority of the target than to their own merits. This question may, 



* Chemical News, vol. xxiv., p. 99. 



