CHEMISTEY. 



89 



Mean of 

 Ozone. 



TABLE II. 



Showing the Mean Reading of the Barometer, Mean Tem- 

 perature, and Daily Mean of Ozone at the Commence- 

 ment and Termination of Phosphorescence of the Sea, 

 between Latitudes 58' and 79 N., and Longitudes 6 E. 

 andST W. 



Phosphorescence. Barometer. Thermometer. Ozone. 



Commencement of ... 29.46 ..... 34.8 .... 2.9 

 Termination of ....... 29.65 ..... 30.0 .... 1.5 



TABLE III. 



Showing Mean of the Barometer and Thermometer, and 

 the Daily Mean of Ozone, with Commencement and Ter- 

 mination of Periods of Luminosity of Phosphorus, de- 

 duced from the Observations of Six Years (on Land). 



Periods of Luminosity Mean of Mean of 



of Phosphorus. Barometer. Thermometer. 



Commencement.... 29.640 ..... 47.3 ..... 5.0 



Termination ....... 29.734 ..... 43.4 ..... 3.0 



By these results, it appears that the phosphores- 



cence of the sea and luminosity. of phosphorus occur 



under similar atmospheric conditions. 



Amount of ozone the day before phosphorescence 0.8 



" " day of " 2.5 



" " day after ^ 1.9 



Of auroral displays, one was without ozone, and 50 



per cent, were accompanied by phosphorescence. 



Absorption of Gases ly Charcoal. In his 

 course of lectures before the Royal Institution 

 on chemical changes of carbon, Mr. William 

 Odling gave the results of experiments, made 

 by him to determine the absorbing power 

 of charcoal upon various gases. He used for 

 the purpose 1 cubic inch of cocoanut-shell 

 charcoal, and found that quantity would ab- 

 sorb gases as follows: oxygen, 18 cubic inches; 

 carbonic gas, 68 do. ; sulphuretted hydrogen, 

 100 do.; ammonia gas, 170 do. The lecturer 

 then went on to say: "Now, you can scarcely 

 form any idea of the amount of force which is 

 required for that absorption. If we were to 

 take 2 cubic inches of oxygen, and endeavor 

 to compress them into the space of one, we 

 should require the pressure of 15 Ibs. weight ; 

 but to compress 18 cubic inches of oxygen into 

 the space of 1 cubic inch, we should require 

 eighteen times 15 Ibs., which would be equiv- 

 alent to about two hundredweights and a half. 

 Here is a half-hundredweight, and it is almost 

 as much as I can lift. Now, we should require 

 about five such half-hundredweights to com- 

 press 18 cubic inches of oxygen into the space 

 of 1 cubic inch ; but you must observe that the 

 cubic inch of charcoal which can absorb these 

 18 cubic inches of oxygen appears to be already 

 full of the -substance of the charcoal itself. 

 There seems to be scarcely any space left ; and 

 what gas the charcoal will contain must occupy 

 its pores. Now, if we imagine that the pores 

 occupy even as much as a twentieth part of 

 the whole mass, we should then require, not 

 five times, but about one hundred times the 

 pressure of this half-hundredweight, to com- 

 press 18 cubic inches of oxygen into a cubic 

 inch of charcoal. Nevertheless, so great is the 

 absorptive power of this kind of charcoal that 

 it gradually exerts upon the oxygen a com- 

 pressing effect equal to the force of some 50 

 hundredweights." 



New Explosive Powders. M. Designolle has 

 invented a new system of powders, of which 



carbozotate or picrate of potash is the base.' 

 His researches upon the subject were under- 

 taken with a view to supply the peculiar wants 

 of breechloading arms. The Bulletin de la 

 Societe de Encouragement gives a description 

 of the powders, of which the following abstract 

 is prepared by the Chemical News: "These 

 powders are of four kinds viz., a musket 

 powder, gunpowder for short-bore cannons, 

 slow gunpowder for cannons with long bores, 

 and an explosive powder for torpedoes and 

 projectiles destined for the undermining of for- 

 tifications. The principal advantages of these 

 new powders are the following: Increase of 

 balistic power without increase of explosive 

 power; the base remaining the same, possi- 

 bility of regulating and varying the effects be- 

 tween the limits of one to ten ; also of regulat- 

 ing, at will, the rapidity of combustion of this 

 powder, and of increasing the balistic power 

 without changing the mode of manufacture. 

 Other advantages are regularity in the man- 

 ner of action ; suppression of sulphur, and con- 

 sequently of the vapors of sulphide of potas- 

 sium and sulphuretted hydrogen; absence of 

 action on metals and almost entire suppression 

 of smoke. Into the explosive powders only 

 two components enter picrate of potash and 

 nitrate of potash ; the musket and gun powders 

 contain carbon in addition to the above-named 

 ingredients. To prepare these powders, the 

 ingredients are beaten from three to six hours 

 with a proportion of water varying from 6 to 

 14 per cent., according to the nature of the 

 mixture ; the powder is condensed by means 

 of the hydraulic press, with a pressure of from 

 30,000 to 100,000 kilos., graining the powder, 

 and pressing and drying it according to the 

 methods employed for the black powder. In 

 order to increase the balistic power, the rela- 

 tive proportion of picrate of potash in the 

 mixture must be increased. For musket-powder 

 it has been proved that not more than 20 per 

 cent, of picrate of potash is required, while for 

 gunpowders its proportion varies from 8 to 15 

 percent. This component (picrate of potash) 

 is of a beautiful golden-yellow color, and crys- 

 tallizes into prismatic needles possessing a 

 brilliant reflection ; it is insoluble in alcohol, 

 but soluble in about 260 parts of water at 15 

 or 14 parts of boiling water. Heated with care, 

 it becomes orange red at a temperature of 

 300, but, on cooling, it assumes its original 

 color. Heated to 310, it detonates with vio- 

 lence. The researches of M. John Casthellaz on 

 the action of nitric acid on phenic acid improved 

 the method of manufacturing picric acid, and 

 produced chemically pure picrate of potash at 

 such a reasonable price that the new powders 

 are not more expensive than ordinary black 

 powder." 



An explosion with most disastrous effects 

 occurred in Paris at an establishment where 

 powders were manufactured, into the compo- 

 sition of which picrate of potash entered, along 

 with (as conjectured) the chlorate of potash. 



