



118 'Scientific Intelligence* ^..i 



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It should be remarked that the presence of a large quantity of nitre 

 has no influence upon this test, as with pure water it gives no color- 

 The same reaction answers also for the hyponitrates. 



The next step is to convert this test into one for the nitrates. The 

 decomposition of the titrates of lead and mercury by boiling with ex- 

 cess of their respective metals, has long been known. The reaction 

 of metals with the alkaline nitrates does not seem to have been studied. 

 I find that nitrate of ammonia is readily decomposed in presence of 

 metallic lead, and what seems surprising, nitrate of potash is also 

 decomposed, though not so readily. 



To test for the nitrates, we have only to agitate the slightly warmed 

 liquid, for a kw minutes, with shavings of lead, and proceed as before. 

 By a longer digestion more of the salt would be converted into nitrite, 

 «nd the color would be stronger. In estimating the delicacy of this 

 process, I had used pure rain water, but before completing the experi- 

 ments I was obliged to be absent for several days; on my, return, I 

 soon found that the water from the same cistern contained so much of 

 nitrates and nitrites, that it could no longer be used. From the readi- 

 ness with which the decomposition was effected, I presume that nitrate 

 of ammonia was present. The interval had been marked by the occur- 

 rence of frequent and severe thunder showers. 



By using distilled water, I have been able to detect the presence of 

 one pint of nitre in about 60,000 of water, digesting with lead for only a 

 short time. Mercury containing a minute quantity of lead, seems to 

 answer better than lead, for a time, in the above process ; but after long 

 use it loses its effect. It will not answer to add to it any perceptible 

 quantity of lead, as the liquid then becomes muddy on agitation. 



Oxalic, tartaric, and dilute hydrochloric acids may be substituted for 

 the acetic, except when they produce precipitates, which would destroy 

 the clearness of the liquid. 



The yellow color produced in this test is the result of a complex 

 decomposition. Everitt's yellow salt, and red prussiate, seem to be 

 formed, and in some cases also very minute quantities of Clayfair^s 

 nitroprussid. 



II. Geology. 



1. On the Parallelism of Mountain Chains in America; by Mr. De- 

 soR, (Proc. Boston Soc. Nat. Hist., Dec, 1850, p. 380,)— It is gen- 

 erally admitted that the Appalachian or Alleghany chain was raised 

 during the deposition of the coal formation. It is consequently referred 

 by Mr. Beaumont to his system of the Balloons, the direction of which 

 (E. 16^ S.), when transferred to Washington, becomes E. 43° 18' N., 

 a direction which indeed answers pretty accurately to that of the main 

 portion of the Alleghany chain. This is also, according to Dr. C. T- 

 Jackson, the main direction of the hills of New Hampshire and Maine- 

 But there is besides in the Alleghanies another direction more nearly par- 

 allel to the meridian, which Professor Rogers considers as a mere devia- 

 tion from the main direction, whereas Mr, Beaumont refers it to a pre- 

 vious upheaval, together with those ranges of hills \n Massacljuselts 

 which Prof. Hitchcock has designated as the ''oldest meridional system, 



