The daily morning journal and courier., 1899-12-28

tween oxygen and hydrogen rests or
 one single chemical combination, an6
 upon two processes for determination
 The first is, the synthesis of water
 from it's components. The second is
 the determination of the densities of
 the gases, and of their volumetric ratio
 Let us consider these in order.
 What synthetic experiments should l be repeated? We are met by the fact
 that a complete synthes,s, in which hy- l drogen and oxygen and water are all l three weighed, can be made with er-
 TOTS only about one-fourth as large. as
 the errors in any of the syntheses where ! only two substances are weighed out
 of the three concerned. Other things
 being equal, then, this process is by
 far the most promising. But, so far, it
 has been carried out adequately by
 only one experimenter Conditions | were varied somewhat, it is true, but by no means as much as they would
 be varied if the same person repeated the experiments after an interval of years; by no means, as If other observ-
 CTS were to undertake such complete | syntheses. Lately, KeiSer has devised
 a process which varies in many par ticularS from that already executed it is very desirable that he should make
 series of experiments, after adequate study of sources of error and of means of avoiding them. It is also desirable
 that, if possible, the original process
 of complete synthess should be repeat
 ed with the little notifications which time is sure to introduce. These two
 would be enough, as far as synthesis is concerned unless indeed, through the invention of another process by third eXperimenter we could have still more. Other syntheses of water than by a complete synthess Seem less likely to
 be of much service, except as school Of experimentation.
 What further work is desirable on
 the ratio of densities and of combining volumes of hydrogen and oxygen?
 Three constants are involved. the den-
 sity of oxygen, the density of hydl ogen,
 and the voumetric ratio.
 The density of oxygen is known with
 probable error of about one part in
 fifty thousand. It is very probable that
 no number whatever of further deter
 minations would change this value by
 one part in ten thousand No further
 work upon this density seems at pres ent desirable; except that whoever de-
 termines the density of hydrogen can
 not well fail to determine that of oxy-
 gen also.
 The density of hydrogen demands further experiment, It is possible to make by some one of three CT four slightly different processes, a series of experiments whose average variation shall be less than one part in three thousand, or five thousand, or even ten thousand, But different series do not agree sufficiently with each other. We are far from knowing the density of hydrogen SO well that more observa- tions might not change our value by one part in two thousand or three thousand. It is very desirable that further observations should be un- dertaken by at least two diff fer mt methods. In one method hydrogen should be weighed while ab- sorbed in palladium, should be than transferred to a measuring apparatus without the use of stop cocks, and should be there measured. This pro- cess should be repeated with measuring apparatus of varied volumes. In an- other method, hydrogen should be weighed after Regnault's method, in oounterpoised globe, but with such pre- cautions that leakage through a stop cock, and contamination with vapor of mercury, should be excluded. The globa should be exhausted till the remaining air is small fraction of milionth. should be sealed off from the pump. and should be connected with a con denser at the temperature of liqud air, so as to remove mercurial vapor. Af- ter this, hydrogen is to be admitted. without the use of stop cocks. The manipulation is not difficult, and the method would confirm the results of the previous method
 The ratio of the combining volumes of Hydrogen and oxygen is not known I with the degree of confidence which is 1 desirable. The history of the matter is not an uninteresting one Further con- | tinuance of the two series of experi- ments on which the present, value de- pends would be most unlikely to change 1t by one part in ten thousand: for it's [ probable error in one part in forty l thousand. But one of the experiment. | CTS has obtained results differing from ! that finally adopted by as much as L one part in two hundred twenty The | other eXperlmenter has entirely dis carded the result of one series, and [ replaced it, not by better series of the same kind, but by one of quite different nature, not carried to it's proper completion, and accordingly re- duced by the use of the constants of van der Waals' equation. It is desira- ble that experiments be made to fur nish means for a new reduction. by the change of volume when two volumes of hydrogen and one vol ume of oxygen are mixed, being at the same pressure before and after mix ing. This experiment has lately been made by Berthelot; whether with suffi- cient precision for the purpose Is not known at this moment. It is also de- slrable that the ratio of the combining of oxygen and hydrogen should be measured with the cases contained in vessels of the dimensions of those used for obt aiming thsir densities
 If these syntheses and these studies If ratios of densities and combining soluIAes should agree as well as 1t is safe to expect, we should know the atomic weight of oxygen as confidently IS we can know it while the value rests pn single chemical process-the com