460 
NATURE 
[Marcu 14, 1907 
Palms generally rank among the most important 
tropical plants, and along the Amazon and its tribu- 
taries, especially near the embouchure, they form 
such prominent objects in the landscape that all 
voyagers make special mention of their luxuriance 
and variety. Dr. Huber devotes a number of plates 
to different species. Phytelephas microcarpa, that 
yields vegetable ivory, the Tucuma and Mumbaca 
palms, both species of Astrocaryum, the Javary, 
another species of the same genus, bearing spines 
on the young trunks, and the Bussu, Mantcaria 
saccifera, producing huge, almost entire, leaves, are 
illustrated in the first two parts. No less interesting 
are Cocos inajas, with pinnz arranged in bundles 
on the leaves, the Baccaba or wine-palm, Oenocarpus 
distichus, remarkable for the distichous arrange- 
ment of the leaves, and the Urucury, Attalea excelsa, 
which provides the Seringueiyvo, or rubber collector, 
with nuts used in smoking the rubber. Of trees other 
than palms, the famous Para rubber tree, Hevea 
brasiliensis, Dipteryx odorata, the source of the Tonca 
bean of commerce, Bertholletic excelsa, the superb 
tree yielding brazil-nuts, and the magnificent 
Caryocar villosum are selected for representation. 
Dr. Huber has also chosen some illustrations of 
typical plant formations, including the littoral vege- 
tation on the river Couany, where the Aninga, 
Montrichardia aborescens, is growing on the shore; 
scenes from some of the tidal creeks or channels 
known as ‘‘igarapés’’; plant formations occurring 
in inundated localities, showing in one case a fine 
development of Ipomoea fistulosa, in another a wide 
expanse of Panicum amplexicaule; and a view of an 
Indian plantation with manioc and sugar-cane in the 
foreground, and the characteristic Imbauba, Cecropia 
peltata, beyond. 
The illustrations are admirable, owing to the care 
that has been exercised in selecting fine specimens 
and suitable situations from which the characteristic 
features of the plants can be brought into the photo- 
graphs. 
By 
van 
Cams, and the Principles of their Construction. 
George Jepson. Pp. 60. (New York: D. 
Nostrand Co.) Price 8s. net. 
In this work examples are given of the design of 
cams of various types, including cylindrical, conical, 
face, and spherical cams, and of different degrees of 
complexity, from the simple heart-shaped cam 
employed in winding bobbins to the writing cam with 
the differential motions of paper and style. The 
illustrative drawings are accurately and beautifully 
execute’, the construction lines being printed in red 
ink for the sale of extra clearness. It is shown how 
to design the profile of a cam so as to give a simple 
harmonic motion or a uniform acceleration and re- 
tardation to the follower, thereby effecting a change 
of position of the latter with a minimum wear and 
tear. The book is a welcome addition to the some- 
what scanty literature on the subject. 
Rivetage. By M. Fricker. Pp. 168. (Paris: 
Gauthier-Villars and Masson et Cie., n.d.) 
Tus little volume belongs to the ‘“* Encyclopédie 
scientifique des Aide-mémoire’’ series, to which 
attention has often been directed in these columns. 
It is divided into two parts; the first passes in review 
the rules—for the most part empirical—which are 
adopted in determining the dimensions of rivets and 
in riveting generally, and the second describes the 
methods which are employed in the actual processes of 
riveting. 
NO. 1950, VOL. 75 | 
LETTERS TO THE EDITOR. 
[The Editor does not hold himself responsible for opinions 
expressed by his correspondents. Neither can he undertake 
to return, or to correspond with the writers of, rejected 
manuscripts intended for this or any other part of NATURE. 
No notice is taken of anonymous communications.] 
A New Mud-Volcano Island. 
ApMiRAL FieLp’s letter in Nature of February 28, 
embodying Commander Beauchamp’s description of a new 
island recently discovered by him about nine miles north- 
west of Cheduba (not Chebuda) Island, off the coast of 
Arakan, leaves no room for doubt that the island in ques- 
tion was due to the eruption of a submarine mud volcano. 
Ramri and Cheduba, together with the adjacent sub- 
ordinate islands, are composed mainly of shale and sand- 
stone (probably of Tertiary age), containing some coal, 
and also very considerable quantities of petroleum, accom- 
panied by inflammable gas. There is evidence of a certain 
degree of abnormal subterranean heat, although such is 
far lower than that associated with true volcanoes, which 
do not exist, nor have any volcanic rocks been observed. 
Mud volcanoes are fairly numerous, which, _ besides 
emissions of a quieter character, are subject, at uncertain 
intervals, to violent paroxysmal eruptions. At such times 
mud and stones are shot out with great force and noise, 
accompanied by large quantities of inflammable gas, which 
in many cases catches fire, and gives rise to a volume ot 
flame that lights up the country for miles around. There 
are numerous well-authenticated descriptions of such 
occurrences, more than one of which were submarine. 
The stones ejected are all derived from the stratified rocks 
mentioned above, the shales furnishing the source of the 
mud. Electric sparks, produced by the friction of the 
ejecta amongst themselves, probably cause the ignition of 
the gas. Some of the recorded paroxysms were 
synchronous with earthquakes. 
A somewhat detailed account of the mud volcanoes may 
be found in the ‘* Records of the Geological Survey of 
India,’’ vol. xi. (1878), pp. 188-207, and descriptions of 
several later eruptions in subsequent volumes. 
Ealing. F. R. Matter. 
A New Chemical Test for Strength in Wheat. 
Tue principle of the test for strength in wheat flour 
described as new by Mr. T. B. Wood in a recent issue of 
NaturRE (February 21), and further claimed by Dr. E. 
Frankland Armstrong (NaTurRE, March 7) as having been 
in regular use in his laboratory during the past year, was 
employed by me more than four years ago, and still forms 
an important factor in my physicochemical method of 
gauging the baking qualities of wheat flour. 
I can fully corroborate Mr. Wood’s opinion that no 
single factor is capable of measuring the strength value 
of wheat, and Dr. Armstrong’s statement that the problem 
is one in which no small number of variables must be 
dealt with. 
In 1905 Mr. A. E. Humphries supplied me with five 
samples as tests of the accuracy of my system as then 
elaborated. I was, however, not successful; but, on re- 
ceiving Mr. Humphries’ views of their baking qualities, 
the cause of my failure was at once apparent. When in- 
vestigating the relation of chemical composition to baking 
qualities, I had relied for the latter data upon loaves 
baked in tins, whilst Mr. Humphries based his opinions 
upon self-supporting loaves of the ‘“‘cottage’’ type. It 
thus became evident that it was necessary to view the 
analytical data from a standpoint suited to a definite 
system or method of baking. That different systems of 
baking require different types of flour explains why millers 
occasionally receive both commendatory and condemnatory 
remarks from their customers on the quality of the same 
blend of flours. 
I hope soon to have an opportunity of publishing some 
of the results of my investigations of the correlated factors 
determining the blending qualities, strength, and texture 
| properties of wheat flour. 
