( HKMISTUY. 



87 



in tho theory, or M unwilling to renounce it 



tiling l>ftter presented itself. 8ir B. C. Brodio 

 anil )'r. Oill'mg both n^rve tlmt tho science of clu-n,- 



.. illii-r iv'iuirvs nr pro\v . tliu utuinio theory ; 

 \\htlr tin- t'oniii-r points out that tho true basis of 



ionco is to bo sought in the investigation of the 

 lw of gaseous combination, or the study of the ca- 

 jiacity i>i' li.iilii-s for hunt, ruthor than in committing 

 ourselves to assertions incapable of proof by chemi- 



Agreeing in tho main mvself with tho opinions of 



t chemists, and believing that we must well 



ilist'miruisli between fact and theory, I would remind 



you that Dalton's discovery of the laws of multiple 



uiul reciprocal proportions (I use Dr. Odling's phrase- 



i, as well as the differences in the power of hy- 



i replacement in hydrochloric-acid water, ain- 



i. and marsh-gas, are facts, while the explana- 



tion upon the assumption of atoms is, as fur as ohera- 



i-iry is as yet advanced, a theory. 



It', however, the existence of atoms cannot be 

 proved by chemical phenomena, we must remember 

 tluit the assumption of the atomic theory explains 

 chemical facts, as the undulatory theory gives a clear 

 view of the phenomena of light ; thus, for instance, 

 one of the most important facts and relations of mod- 

 ern chemistry, which it appears difficult, if not im- 

 possible, to explain without tho assumption of 

 atoms, is that of Isomerism. How otherwise than 

 by a different arrangement of the single constituent 

 particles are we to account for several distinct sub- 

 stances in which the proportions of carbon, hydro- 

 gen, and oxygen, are the same ? Why, for instance, 

 should 48 parts, by weight, of carbon, 10 of hydro- 

 jjon, nnd 16 of oxygen, united together, be capable 

 of existing as three different chemical substances, 

 unless we presuppose a different statical arrangement 

 of the parts by wnich these differences in the deport- 

 ment of the whole are rendered possible ? If ; then, 

 it bo true that chemistry cannot give us positive in- 

 formation as to whether matter is infinitely divisible 

 and therefore continuous, or consists of atoms 

 and is discontinuous, we are in some degree as- 

 sisted in this inquiry by deductions from physical 

 phenomena which have been recently 'pointed out 

 by the genius of Sir William Thomson. jProf. 

 Koscoe here made reference to the article in Aature, 

 the substance of which is given ante.] There is, 

 however, another class of physical considerations, 

 which renders the existence or indivisible particles 

 more than likely. I refer to the mechanical theory 

 of gases, by means of which, thanks to the labors 

 <>t' t mment English and German philosophers, all tho 

 physical properties of gases their equal expansion 

 bv heat, the laws of diffusion, tho laws of alteration 

 or volume under pressure can be shown to follow 

 from tho simple laws of mechanical motion. This 

 theory, however, presupposes the existence of mole- 

 cules, and in this direction, again, we find confirma- 

 tion of the real existence of Dalton's atoms. 



Hydrogenium-Amalgam. Prof. O. Loew, of 

 New York, communicated to the New-York 

 Lyceum of Natural History, in April, the fruits 

 of his experiments upon the production and 

 properties of this (supposed) compound. He 

 obtains the hydrogenium-amalgam on a large 

 scale by shaking up zinc-amalgam, contain- 

 ing only a few per cent, of zinc, with an 

 equal volume of the solution of bichloride 

 of platinum, containing about 10 per cent, of 

 the chloride, care being taken to keep the 

 mixture cool. The zinc-amalgam then absorbs 

 hydrogen, and, on being removed from the 

 mixture, evolves it, till the decomposition of 

 the amalgam is complete. The volume of the 

 hydrogen thus developed is from 100 to loO 



times that of the mercury employed. It hun a 

 faint but peculiar odor. When the hydro- 

 genium-amalgam is jmsst.'d, directly after its 

 preparation, between sheets of filtering-paper, 

 and spread out, in a layer not too thin, to the 

 air, its temperature soon rises considerably, 

 and vapor of water is formed, which may bo 

 condensed in a glass receiver. Tho finely- 

 divided platinum present is obviously the cause 

 of this rapid oxidation. If, after this, it is 

 washed with water, it undergoes a very slow 

 decomposition ; the volume increases, and bub- 

 bles of hydrogen escape through the water 

 above. An addition of zinc-amalgam or sodi- 

 um-amalgam greatly accelerates the decompo- 

 sition of the hydrogenium-amalgam. 



Platinum after perfect amalgamation does 

 not act as energetically as in its nascent state ; 

 i. e., when precipitated on the amalgam. "When 

 platinum-amalgam is mixed with zinc-amalgam, 

 tho decomposition of tho water by zinc is ex- 

 tremely slow, and the hydrogenium-amalgam 

 does not appear for some time. Under certain 

 conditions, moreover, the hydrogenium-amal- 

 gam is formed without the aid of platinio 

 chloride. Prof. Chandler had at one time about 

 twenty pounds of mercury containing zinc, 

 which was left standing in a bottle with water 

 for three weeks ; the hydrogenium-amalgam 

 formed on the surface of the mercury gradually 

 decomposing above and being renewed from 

 below. 



Constitution of Ammonium-Amalgam. 

 Prof. Charles N. Seely read a paper on this 

 subject before the New- York Lyceum of 

 Natural History. He regarded the so-called 

 ammonium-amalgam to be a mechanical or 

 physical mixture of liquid mercury with the 

 gases, ammonia, and hydrogen, and that its 

 semi-solid consistency is due to the mixture 

 having the nature of a froth. 



The principal considerations by which this 

 view of the constitution of ammonium-amal- 

 gam has been reached are as follows: 



1. The volume of ammonium-amalgam is inex- 

 plicable in any other way ; it is utterly inconsistent 

 with the well-established laws of combinations by 

 volume. There is no case of a liquid or solid chem- 

 ical compound or amalgam which has any analogy 

 to it. 



2. Mercury has a mirror-like surface, while am- 

 monium-amalgam has comparatively a whiter and 

 more dead surface; it approaches in appearance to 

 matt silver. Such changes are characteristic of 

 froths. 



3. If ammonium-amalgam be subjected to varying 

 pressure, its volume changes apparently in accord- 

 ance with Mariotte's law of gaseous volume.' To 

 illustrate this important fact, a glass tube one-third 

 of an inch in diameter, twenty inches long, and fitted 

 with a plunger, was employed. Mercury containing 

 a little sodium was poured into the tube to one-third 

 of an inch in depth, and upon this was poured a 

 strong solution o^ chloride or ammonium, occupying 

 about two inches in length of the tube. The ammo- 

 nium-amalgam was completely formed in a few min- 

 utes, and occupied several inches of the tube. On ad- 

 justing and depressing tho plunger, the volume of the 

 amalgam progressively diminished till it closely ap- 

 proached the original volume of the amalgam. *Also 



