400 
NATURE 
[August 26, 1886 
as the impossibility of selecting a representative diagram of the 
mean work of the steam that should be sufficiently accurate for 
showing the mean power developed in the cylinders during the 
whole of the test, rendered it hopeless to estimate the effect which 
the jackets had upon the state of the steam in the cylinders.” 
The comparisons were on this account only available with tests 
made when the jackets were not at work. The following were 
the final conclusions arrived at :—For the same consumption of 
water and fuel per hour, the work done by the compound engine 
is greater than that done by the ordinary engine; for the same 
boiler-pressure and the same speed, the increase of work done 
by the compound engine compared with ordinary engines 
diminishes in proportion as the total consumption of fuel and 
water increases. 
Mr. Sandiford’s experiments were made on two locomotives 
which had been sent into the shops for heavy repairs, both of 
them requiring new cylinders. One was arranged with two high- 
and two low-pressure cylinders, and the other with one high- and 
one low-pressure cylinder. The compounding of both locomo- 
tives was attended with economy in consumption of fuel, and 
they were decidedly more powerful than the original engines 
had been, whilst from the drivers’ point of view they were not 
more complicated. 
The views held by the members taking part in the discussion 
agreed generally with those of the authors of the papers as 
regards the benefits both of jacketing and of compounding 
locomotives. 
After the close of the discussion, the members visited various 
works in and around London, amongst those most favoured 
being the Royal Mint, Lambeth Pottery, the Royal Small- 
Arms Factory (Enfield), the Royal Arsenal (Woolwich), Beckton 
Gas-Works, the Royal Victoria and Albert Docks, Tilbury 
Docks, and the Crossness Sewage-Works of the Metropolitan 
Board of Works. 
PROGRESS OF CHEMISTRY AND 
MINERALOGY 
M FRIEDEL, President of the French Association which 
* met recently at Nancy, gave an address on the progress of 
chemistry and mineralogy. After briefly referring to the ravages 
made by death amongst the founders of the Society, and to the 
prospect of its amalgamation with the Scientific Association 
of France, M. Friedel proceeded to remark that the pro- 
gress of chemistry during a period of thirty years had been set 
forth with masterly clearness and attractive eloquence by the 
late M. Wurtz at the gathering held at Lille in 1874, and two 
years later at the Clermont Conference. The theoretical con- 
quests resulting in the discovery of the brilliant coal-tar dyes, 
the reproduction of alizarin and the other colouring substances 
of madder, of vanilline (the odoriferous principle of vanilla), of 
indigo, of the tartaric and citric acids, &c., continue their pro- 
gressive and pacific career. 
The study of countless artificial compounds brings us daily 
nearer to the natural compounds that have not yet been repro- 
duced, and the most important alkaloids, such as quinine and 
morphine, seem already almost within the scope of synthetical 
chemistry. The work that has been undertaken in their regard 
resembles that of architects engaged in raising stone by stone 
the plan of some edifice at once of intricate design and difficult 
access. 
This plan once securely established, the reconstruction of the 
building itself will no longer lie beyond the power of those 
regular synthetic methods which are daily acquiring greater 
expansion, It will soon be a mere question of patience and 
intelligent work, and the time is approaching when quinine and 
morphine will be produced as readily as alizarin now is. Nay 
more, there is reason to hope that besides the natural alkaloids 
others will be obtained endowed with valuable therapeutic pro- 
perties. While endeavouring to reproduce atropine, whose 
synthesis he afterwards succeeded in making, M. Ladenburg 
has obtained homatropine, which produces physiological effects 
sufficiently distinct to claim, side by side with its homologue, a 
place amongst the agents employed by oculists. Other less suc- 
cessful essays have also shown in the derivatives of quinoline 
that patients have perhaps been somewhat prematurely treated 
with agencies producing a vigorous and very special action on 
the organism. 
Ifsynthetic chemistry has a bright future, we shall also doubtless 
see the development of another branch of chemistry which has 
hitherto been comparatively neglected, after having been held in 
honour at the beginning of the century, and found in Braconnot, 
of Nancy, an able and devoted cultivator. M, Friedel referred to 
the research of direct principles, that is to say, of the chemical — 
compounds which exist in animals and plants, and which may be ~ 
extracted from them. Similar alternatives are often presented 
in the history of science, which proceeds with irregular leaps, — 
as results from the very nature of things. ‘) 
The separation of the direct or immediate principles had first — 
to place at the disposal of chemists abundant materials of varied — 
composition, in order to fix their attention on the complexity of | 
organic substances. Then came the time to seek the laws 
determining their constitution, and now that these laws are 
sufficiently understood to establish the structure and functions of — 
many of them, the more complete study of their transforma- 
tions, the more accurate definition of some already determined, — 
j 
the certain discovery of many others still unknown, must attract — 
further attention to the work of those who, like Braconnot, 
have made a special study of the natural products. 
Mineral chemistry has at last succeeded, in the hands of a | 
young and skilful naturalist, in obtaining the isolation of fluorine, 
which had been in vain attempted by so many other students. 
This important result is again due to the process used by Davy 
for isolating potassium—the decomposing action of the pile. — 
The essay had already been made, but under conditions in which 
this exceptionally active «element reacted on the electrodes or on 
the vessels. M. Mois<an’s merit consisted in perceiving that the 
decomposition should be made at a low temperature, and in the : 
happy choice of the substance to be subjected to the process of 
of fluoride of potassium. In the gaseous current disengaged at 
electrolysis—hydrofluoric acid made conductive by the addition 
the positive pole, crystallised silicium and boron burn at the 
ordinary temperature, iodide and chloride of potassium are de- : 
composed, mercury and other metals transformed to fluorides, 
organic compounds carbonised or inflamed, while water absorbs 
the gas, yielding in its place ozonised oxygen. Thus is produced 
a large number of reactions, whose study promises a most inter- 
esting sequel to this brilliant discovery. 
Physico-chemical research continues on its part to furnish 
means of investigation enabling us to penetrate more deeply into 
the very life of the chemical molecule, that is, those inner 
movements whose existence must now be admitted. 
Spectroscopy, which has just yielded to M. Lecoq de Bois- 
baudran two new metals, reveals, by the comparison of the rays, 
a connection, which is assuredly far from accidental, between 
the various elements of the same family. 
Thermo-chemistry, after having, in the hands of M. Berthelot 
and M. Thomsen, given the reason of most reactions, now 
approaches the study of isomeric bodies. M. Bouty’s researches 
on the conductivity of the solutions of salts, and those of M. 
Raoult on the lowering of the freezing-point of the various solu- 
tions, seem to supply fresh means for determining the molecular 
weight of compounds. 
But our attention must now be directed to mineralogy, a far 
less popular science than chemistry. 
After being held in considerable esteem at the close of the 
last and beginning of the present century, when Werner’s 
labours enabled mineralogists to describe and. methodically 
classify the rich materials accumulated in collections, mineralogy 
lost its votaries according as it became more scientific. The 
immortal labours of Haiiy, of Berzelius, and the chemical school, 
seem to have scared the amateurs, who probably saw in mine- 
ralogical collections little more than so many picturesque speci- 
mens distinguished by their diversified colours and fantastic 
forms. 
Mineralogy presents the special character that it profits by the 
progress of chemistry and physics, for which it has itself often 
enough supplied the starting-point. Aiming especially at the 
description. of crystallised minerals, it applies to this description 
methods which are afterwards profitably transferred to the 
domain of artificial products. 
Thus it has given birth to crystallography, which establishes 
the laws determining the formation of crystals—those marvellous 
products of the mineral world in which Haiiy recognises the 
regular aggregations of infinitely minute particles. 
This regularity of structure, indicated at once by their out- 
ward form, has been confirmed by the study of their many 
physical properties, especially that of their action on light. 
From this study has been derived one of the safest and most fruit- 
ful processes by which the inward architecture of crystals has 
