March 30, 1872.] 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
795 
rity of chemists, a conviction of the utility, if not the 
absolute truth, of the atomic theory. It is a fact that, 
contrary to a statement recently made by a speaker at 
one'of the meetings of the Chemical Society, molecular 
ideas have implanted themselves very firmly in the 
minds both of chemists and physicists. With the latter, 
indeed, the existence of molecules, or physical atoms, is 
no longer a matter of question, several distinguished 
men having gone so far as to calculate the limits within 
'which the magnitude of molecules must lie. It is much 
to be regretted, however, that the tendency of thought 
\\ ith regard to the ultimate constitution of bodies is still 
80 distinctly statical. We have much reason to believe 
that even atoms which are united together by chemical 
bonds are in motion, and that the atoms constituting a 
molecule are to a certain extent free to move about, and 
do move around or amongst each other. As to certain 
knowledge, however, concerning the nature of the force 
which binds them together, and of the laws which regu¬ 
late chemical action, we possess but little more than the 
chemists of half a century ago, and we really seem to be 
making hut feeble efforts to get out of this condition of 
stagnation. It is true that thermo-chemistry is being 
at the present time prosecuted with a little iaore acti¬ 
vity, but in every laboratory the phenomena accompany¬ 
ing chemical reactions need to be more carefully ob¬ 
served and recorded before we can hope for further light 
in this direction. 
In the Supplement to Watts’s ‘ Dictionary ’ we notice a 
valuable article on atomicity, the moderate tone of which 
is commendable. The existing condition of the subject 
shows how inadequate are our systems of notation to 
Zanzibar : City, Island and Coast. By Richard F. 
Burton. 2 vols. London : Tinsley Brothers. 1872. 
This work deals with a far more limited area than 
most of the recent books on African travel and research. 
The first volume is almost entirely occupied with the 
island of Zanzibar itself, including a description of the 
natural features of the island, its climate, natural pro¬ 
ductions, both animal and vegetable, the ethnology of 
its native tribes, and a slight sketch of its history; while 
the second volume gives details of some short excursions 
along the coast and in the interior of the mainland, but 
covering only a comparatively small district. Great 
credit is due to Captain Burton for the zeal with which 
he has pursued his researches in so unpromising a field, 
under a climate particularly trying to Europeans, in a 
country without any special features of attraction, and 
among native tribes whose habits and personal appear - 
figure, with even a semblance of probability, the true 
nature of chemical compounds. 
There is always some good, however, in a theory the 
use of which leads to practical results ; and it may be 
said with truth, that the study of abstract formulistic 
chemistry has rendered great and valuable assistance in 
exploring new regions and discovering new compounds. 
No more striking example of this could be cited than the 
comparatively recent formation of alizarin, the colour - 
ing-inatter of madder, by a synthetical process, which is 
now worked on a manufacturing scale. 
Turning to that very important subject—the produc- 
tiou of iron—we find that nothing of importance, so far 
as the chemistry of the matter is concerned, has been 
added since the publication of the dictionary, but some 
space is very properly given to a description of Siemeus’ 
valuable “regenerative gas furnace,” and its application 
to the production of steel. 
In the department of physical chemistry science had to 
deplore, in 1869, the loss of Thomas Graham, to whose 
researches we owe almost all the precise knowledge we 
possess of atomic motion. His later experiments on the 
passage of gases through colloid septa, and the absorption 
of some gases by certain metals, receive due mention. 
Then a place is accorded in this volume to spectral 
analysis, the application of which to the examination 
of the light from the celestial bodies is of so great in¬ 
terest that we can hardly grudge it space, although, 
.strictly, it has little to do with chemistry, and is charge¬ 
able with having lured more than one chemist of distinc¬ 
tion from his allegiance to his own department of 
science. A review of Watts’s ‘Supplement’ is sufficient 
to show how serious have been the results of this neg¬ 
lect of general chemistry. In this our day, in fact, 
there is a deficiency of that spirit which animated the 
earlier chemists. There is not much hope of great ad¬ 
vance whilst the philosophers are more intent on dis¬ 
covering the road to fortune than on treading those high 
paths to which the labours of Berzelius and Gay-Lussac, 
Liebig and Dumas ought to have taught us to aspire. 
We feel almost tempted to exclaim:— 
“ Those suns are set. O rise some other such! 
Or all that we have left is empty talk 
Of old achievements, and despair of new.” 
ance are repulsive in the extreme. What we are most 
concerned with is, however, any additions which the au¬ 
thor may have succeeded in making to our knowledge of 
the economical productions of the country. These are 
not numerous; but there are some points of interest. 
The prosperity of the island has hitherto depended on 
the cocoa-nut and the clove-tree. There is an Arab 
saying, that the cocoa-nut-palm and the date-palm can¬ 
not thrive together, and this is fully exemplified at Zan¬ 
zibar, the latter not being a product of the island. The 
cocoa-nut supplies the natives, not only with food, wine 
and spirit, but also with syrup and vinegar, cords, mats, 
strainers, tinder, firewood, houses and palings, boats and 
sails, in short, all the wants of barbarous life. Every 
part of it may be pressed into man’s service, from the 
sheath of the first or lowest leaf, used as a sieve, to the 
stalk of the young fruit, which, divested of the outer 
coat, is somewhat like our chestnut. As many as twelve 
million nuts have been exported in a single year for the 
soap and candle trades. The true oil-palm (Elais gui- 
neensis) does not grow on the island. Cotton is said to 
thrive on the island, but the climate is not favourable. 
Coffee has been attempted, but has been driven out by 
the clove. There are two distinct trees which produce 
caoutchouc. The tamarind, as in India, is a splendid 
tree, but the fruit, though used for acidulated drinks, is 
not prepared for exportation. A smooth-rooted sarsa¬ 
parilla, of lighter colour than the Brazil or Jamaica 
article, is found wild upon the island and the coast. The 
orchilla, yhich gives its name to the Insulae Purpurariae, 
has been tried, and, resembling that of the Somali coun¬ 
try, it gives good colour. The favourite fruits of the 
natives are the mango, orange, banana, pine-apple and 
bread-fruit. The grains in most common use are the 
maize and sesamum. 
But the -most important commercial product of the 
island is the clove, which was introduced from Mauritius 
and Bourbon in 1818. The industry, however, is neg¬ 
lected ; from the natural indolence of the native tribes, 
the trees are not properly trimmed, and the produce is 
inferior in quality to that of Bourbon or the Moluccas, 
and not above one-fourth in quantity of what it should 
be. Nevertheless, as long ago as 1859, the crop amounted 
to seven million pounds, valued at £85,000. 
Captain Burton paid a special visit to the Copal field 
of Sa’adani, on the coast of the mainland opposite Zan¬ 
zibar. He confirms the statement of Dr. Kirk, that the 
Zanzibar copal-tree is the liymeneta verrucosa of Boivin, 
called in the native language Msandarusi. It grows in 
thickets, to the height of about 30 feet, and measuring 
about a yard in girth, upon fiats covered with mimosas, 
Hyphaenes and various other palms. The gum exudes 
from the bole and boughs when injured by elephants or 
other causes. This is the Chakazi, raw copal, whence the 
local English name “jackass copal.” It has rarely any 
“ goose-skin,” and it floats, whilst the older product 
sinks, in water. It produces the magnificent varnishes 
of China and Japan. Dr. Kirk states that the fossil resin 
when first dug up shows no trace of the characteristic 
