Intelligence and Miscellaneous Articles. 237 



order to avoid the necessity for additional sounding apparatus, which 

 would retard th'e communications between the extremities, it would 

 be necessary to limit such intermediate communications to stated 

 periods, so that an observer might be in attendance. 



A trial was made with a tube of one inch in diameter, very nearly 

 two miles in length, returning upon itself, so that both ends of the 

 tube were brought to one place : — the compression applied at one 

 end, was equal to a column of seven inches of water; and the effect 

 on the index at the other end, appeared in fifteen seconds of time. 



Laws have been propounded by eminent men on the expenditure 

 of aeriform fluids through conduit pipes, and of the resistance of 

 the pipes ; but these are not strictly apj^licable to the present ques- 

 tion. Under all circumstances, it seems desirable that experiments 

 on a practical scale, at extended distances, should be resorted to, 

 as the most satisfactory guide, for carrying into effect telegraphic 

 communications of this kind. 



METHOD OF DISTINGUISHING TRAP FROM BASALT. 



Mons. H. Braconnot finds that these rocks may be distinguished by 

 suljjecting them to distillation ; the trap always yields an empyreu- 

 matic ammonlacal product, which restores the colour of litmus paper 

 reddened by an acid, whereas basalt produces no sucli effect; and he 

 presumes that the organic matter which had existed in the materials 

 of the basalt was destroyed by the. volcanic heat by which the rock was 

 produced; whereas he conceives trap to have been formed in water, 

 under the influence of a moderate temperature, insufficient to de- 

 stroy the organic matter which was contained in the debris from 

 which it was formed. The trap was selected from various places, 

 and of unquestionable nature ; and the basalt was that of Clermont, 

 in Auvergne. M. Braconnot has also found that various granites 

 yield ammonia when heated ; and the same effect was jDroduced by 

 serpentine and porphyry; but the gneiss of Freiberg, in Saxony, 

 yielded an acid, which appeared to be the hydro-fluoric. Many 

 other rocks of various kinds were subsequent^ found to yield am- 

 monia. — Annales de Chim. et de Plujs., Jan. 1838. 



ABSORPTION OF AZOTE BV PLANTS DURING VEGETATION. 



M . Boussingault has determined by numerous experiments, made 

 with great care, that, while shooting, wheat and trefoil neither in- 

 crease nor diminish the portion of azote which analysis shows them 

 to contain ; and that during germination, these grains lose carlion, 

 hydrogen, and oxygen ; and that each of these elements, as well as 

 tlie proportions in which the loss occurs, varies at diflferent stages of 

 germination. It appears also, that during the cultivation of trefoil 

 in soil absolutely deprived of manure, and under the influence of air 

 and water only, this plant acquires carbon, hydrogen, oxygen, and 

 a (piantity of azote, appreciable by analysis : wheat cultivated ex- 

 actly iu the same circumstances, also takes from the air and water, 

 carbon, hydrogen, and oxygen; but analysis does not prove that it 

 lius cither lost or gained azote. — Ibid. 



