CHEMISTRY. 



89 



It will be seen, therefore, that there is a 

 steady increase in the quantity of gas produced 

 per pound of fuel consumed, as the water-pres- 

 sure rises from 15 Ibs. to 40 Ibs. Beyond this 

 point there does not appear to be much ad- 

 vantage gained by still further increasing the 

 pressure. The gas produced is essentially a non- 

 luminous gas. When taken direct from the pro- 

 ducer, it burns with a reddish-blue flame. Af- 

 ter having, however, been stored in a gas-hold- 

 er for a few hours in contact with water, the 

 flame loses this red tinge, and the gas burns with 

 a blue lightless flame very much resembling 

 ordinary gas burned in the Bunsen burner. In 

 neither case is there any smoke, soot, or de- 

 posit of any kind by the burning gas, the sole 

 products of combustion being water and car- 

 bonic anhydride. When the gas is made in 

 considerable quantity, its cost in London is 

 about a quarter of that of ordinary illuminat- 

 ing gas. 



The Equivalent of Gallium. Lecoq de Bois- 

 bandran has determined the equivalent of gal- 

 lium by the calculation of gallo-aminoniacal 

 alum, and by igniting the gallium nitrate pro- 

 duced from a known weight of the metal. The 

 slight losses sustained in these two operations 

 affect the value of the equivalent in an opposite 

 manner. The former process gave as the re- 

 sult 70-032 (hydrogen being 1), and the latter 

 69 '698. The mean value, 69-865, may be taken 

 as the first approximation. Considerations 

 founded on a classification of the elements in 

 accordance with their properties and the value 

 of their atomic weights point to a maximum 

 number, 69*97, and a minimum, 69*66 (mean, 

 69 -82). The author enters into some details on 

 the comparison of the spectra of the metals 

 Al, Ga, In, on the one hand, and K, Rb, Cs, on 

 the other, and deduces hence for the equivalent 

 of gallium the value 69*86. 



New Compound of Palladium. In a com- 

 munication to the Paris Academy of Sciences 

 H. Ste.-Claire Deville and H. Debray recite 

 that, on heating a solution of palladium chloride 

 (PdCl) with strong nitric acid in presence of 

 sal-ammoniac, the palladium is converted into 

 an ammonia chloride (PdCl a + NH 4 Cl), which 

 precipitates in small regular octahedrons of a 

 fine red color, sparingly soluble in water, and, 

 like the corresponding compounds of iridium 

 and platinum, almost insoluble in a concentrat- 

 ed solution of sal-ammoniac. The authors ex- 

 pected that in heating with aqua regia certain 

 mother-liquors containing ammoniacal palla- 

 dium chloride (dipalladamine chloride, Pd01 2 



2N~H 3 ) with excess of ammonium chloride, the 

 metal would be entirely thrown down as a 

 double chloride. The result, however, was 

 otherwise ; for, instead of the expected com- 

 pound, they obtained a reddish -black sub- 

 stance, PdaCl 3 2NH 3 , being a combination of 

 ammonia with a palladium chloride hitherto 

 unknown. 



New Process for the Regeneration of Spent 

 Gas-Lime. A new process for regenerating 

 the foul or spent lime of gas-manufacture 

 has been introduced into many gas-works in 

 England. It is known as Bishop's process, 

 and is described in an address delivered by Mr. 

 John Mayer in the Chemical Section of the 

 Glasgow Philosophical Society. In this sys- 

 tem the kiln consists of a series of four calcin- 

 ing chambers arranged vertically over each 

 other, and, together with the furnace under- 

 neath them, occupying the space of one of the 

 ovens of the retort-bench. They are about 9 

 feet long and 2 feet wide. All the chambers 

 are constructed of fire-clay tiles and blocks of 

 similar form. The gases from the furnace 

 pass backward to its farther end, and rising 

 enter, by means of two ports at the corners, 

 the lowermost calcining chamber, thence over 

 the top of and in close contact with the spent 

 lime, to the fore end of the same ; and thence 

 up through two ports as before, traversing the 

 second chamber in the same way ; then the 

 third chamber; and, lastly, the topmost or 

 drying chamber, from which they enter the 

 main flue, the opening into which is regulated 

 by a suitable damper. The spent lime is first 

 charged into the drying chamber by means of 

 a shovel, and it remains in that chamber dur- 

 ing the regeneration of the contents of the 

 chambers underneath; and after the latter 

 have been discharged into an iron wagon or 

 barrow, the contents of the upper chamber are 

 discharged into the lower chambers through a 

 port near the front of each, the opening of 

 which is covered with a suitable tile, as the 

 chambers are successively filled, commencing 

 at the lowermost; and the gases from the fur- 

 nace, while passing over and in close contact 

 with the spent lime, disengage the carbonic 

 acid and other impurities. Air is admitted 

 through ventilating flue-boxes, placed on either 

 side of the furnace near to the ground, whence 

 it is conveyed to and directed against the fuel 

 in the furnace near to the center of the furnace- 

 bars, where it issues from a number of holes 

 about 1% inch in diameter, pierced through fire- 

 clay blocks, which form part of the sides of 

 the furnace. These air-holes pass through the 

 blocks with a dip of about 1^ inch toward the 

 furnace-bars. In practice it is found that one 

 man can attend to two sets of chambers, such as 

 those just described, and regenerate upward of 

 60 cwt. of spent lime per shift of twelve hours, 

 with a consumption of about 8 cwt. of fuel, 

 which is usually the coke of ordinary cannel 

 coal. 



Hydrogen Peroxide. Tne amount of hydro- 



