May 7, 1885 | 
be arranged for lifting the caitridges into the magazine of the 
gun; in this new form the total length of firing apparatus is 
22inches. ‘his arrangement was not described, as the various 
patents for which the inventor had made application, amounting 
to over a hundred in all, were not yet complete. 
On the Ist inst. was read Prof. Kennedy’s abstract of the work of 
the Research Committee of the Institution on Riveted Joints. There 
can be no question of the value of a series of experiments of this 
character, covering in all 290,—64 on perforated (punched and 
drilled) plates, 97 on actual joints, 44 on the tenacity of the 
plates used in the joints, 33 on the tenacity and shearing resist- 
ance of the rivet steel used in the joints, and the rest on various 
other matters connected with them. The whole of the experi- 
ments were made upon soft steel supplied from the Landore 
Siemens-Steel Works, which was found to have a tenacity of 
from 28 to 30 tons per square inch, with an extension of 23 to 
25 percent. ina length of to inches. The limit of elasticity of 
the metal was generally about 60 per cent. of its ultimate resist- 
ance, the percentage of carbon in the plates was given as about 
o'18. 
The main conclusions drawn from these experiments are the 
following :—The metal between the rivet holes has a consider- 
ably greater tensile resistance per square inch than the same 
metal unperforated, the excess tenacity varying from 20 to about 
8 per cent. The shearing resistance of rivet steel is a much 
more variable quantity than the tenacity of steel plate or of the 
rivet steel itself—a result due, Prof. Kennedy thinks, in some 
manner to the want of attention directed to this point, or of 
experiments specially upon it. The size of the rivet heads and 
ends plays a most important part in the strength of the joints, at 
any rate in the case of single riveted joints ; an increase of about 
one-third of weight of metal in the heads and ends increased the 
resistance of the joint 84 per cent., the additional strength being 
no doubt due to the prevention of so great tensile stress in the 
rivets through distortion of the plates. The strength of a joint 
made across a plate is equal to that of one made in the usual 
direction. The intensity of bearing pressure on the rivets 
exercises, with joints proportioned in the ordinary way, a very 
important influence on their strength. The value of hydraulic 
as compared with hand riveting, in the case when sound hand- 
riveting is possible, lies in the increased security and stiffness it 
gives at ordinary working loads rather than in any actual 
raising of the breaking load. 
The experiments point to very simple rules for proportioning 
joints of maximum strength. Assuming a bearing pressure on 
the rivet of 43 tons per square inch, and an excess tenacity of 
the plate of 10 per cent. of its original strength, the diameter of 
the rivet-hole should be 23 times the thickness of the plate, 
and the pitch of the rivets 2§ times the diameter of the 
holes for single riveted joints, while for double-riveted lap-joints 
with the same ratio of diameter to thickness the ratio of pitch 
to diameter should be from 3°64 to3°82. IJfasmaller rivet be 
used than that here specified, the joint will not be of uniform, 
and therefore not of maximum, strength ; but with any other size 
of rivet the best result will be obtained by using a pitch 
calculated from the following formula, viz. :— 
p= ae + d, 
where / is the pitch, @ the diameter of the hole, and ¢ the thick- 
ness of the plate, whilst the mean value of the constant a is 0°56. 
By use of this formula for double-riveted lap-joints it is likely 
that the prescribed size of rivet may be inconveniently large in 
practice. In this case the diameter of the rivet should be taken 
as large as possible, and the above formula will give the pitch, 
by making the constant @ = 1°15 in the mean, For double- 
riveted butt-joints of maximum strength the diameter of the 
rivet hole should be 1°8 times the thickness of the plate, and the 
pitch should be 4'r times the diameter of the hole. 
In a boiler the plate is much more affected by time than the 
rivets, and it is therefore not unreasonable to estimate the per- 
centage by which the plates might be weakened by corrosion 
before the boiler would be unfit for use at its proper steam- 
pressure, and to add correspondingly to the plate area. In this 
case the joint should be proportioned not for the actual thickness 
of the plate, but for a nominal thickness less than the actual by 
the assumed percentage. The joint will thus be approximately 
one of uniform strength by the time it has reached its final 
workable condition, up to which time the joint as a whole will 
not really have been weakened, the corrosion only gradually 
bringing the strength of the plates down to that of the rivets, 
NAT ORE 
PHI 
There is an interesting point to which we propose reference 
on a future occasion, viz. the probable causes to which an 
increase of tensile strength in the remaining material of per- 
forated plates may be due. 
The President, at the conclusion of an interesting discussion, 
referred to the circumstances that the paper was an abstract of 
three years’ work, the experiments having been carried on by 
Prof. Kennedy free of charge to the Institution, whilst the 
material supplied and the work of preparing the various joints 
tested had been performed at prime cost. 
The main feature in connection with the Blooming Mill 
designed by Mr. C. B. Holland, of Ebbw Vale, a paper 
describing which was read, was the application of hydraulic 
power to all the work performed, except that of actually driving 
the rolls. 
UNIVERSITY AND EDUCATIONAL 
INTELLIGENCE 
Oxrorp.—On Tuesday last an effort was made to relieve 
Honour men in the non-classical final schools from the drudgery 
entailed by the present Pass Classical Moderations. Council 
brought forward a scheme substituting a Preliminary Honour 
Examination in each Honour School in lieu of ‘* Pass Mods.” 
Under this scheme the study of the classical languages would 
not be required of any candidate for honours in Natural Science 
or Mathematics after he had passed the present Responsions or 
*« Smalls ;” thus an extra year would be given to the study of 
the subjects chosen for the final schools. Unfortunately for the 
measure, the preamble—mainly of general character—contained 
one clause relating to Mathematics which would have exempted 
mathematical class-men from any literary work, and the preamble 
was therefore opposed by many who approved of its general 
policy but desired an opportunity of discussing or amending the 
Preliminary Examinations to be introduced into each Faculty. 
The preamble, after a long debate, was lost on a division by 
one vote only—71r voting for it and 72 against. No doubt a 
similar measure will be brought forward again. 
SCIENTIFIC SERIALS 
To the number of the Fournal of Botany for March Mr. F. 
Townsend contributes an illustrated paper on the floral envelopes 
of Cyperaceze and Graminez, in which he claims a closer homo- 
logy between the corresponding parts in the two orders than has 
generally been allowed.—Mr. G. Murray has another and 
apparently a final word on the so-called ‘‘sclerotiets” found by 
Mr. A. S. Wilson and Mr. Worthington Smith in the leaves of 
diseased potatoes, and which he demonstrates not to have the 
organic structure attributed to them and to be unconnected with 
the potato disease.—In the number for April Mr. T. Hick gives 
a further observation on the continuity of protoplasm, which he 
finds to prevail throughout the frond of a seaweed belonging to 
a different group from those in which it had hitherto been ob- 
eerved, the common Ascophyllum nodosum (Fucus noaosus).—In 
addition to these papers there are in these two numbers others 
which are descriptive or refer to local botany. 
THE most interesting article in the Wwove Giornale Botanico 
Italiano for January, 1855, is by Signor Cugini on the anatomy of 
the inflorescence and of the flowers of Didon edule. The inter- 
mediate position occupied by the Gymnosperms, and especially 
by the Cycadex, between Cryptogams and the more highly 
developed flowering plants, renders especially valuable any fresh 
contribution towards the knowledge of the structure of their 
reproductive organs. The present paper deals especially with 
the anatomy of the ovule and of the ovuliferous leaves. —The 
greater part of the same journal for April is occupied by a very 
elaborate paper by Signor J. Danielli, illustrated by a number 
of plates, on the structure, distribution, and uses of the 
American aloe, Agave americana,—A shorter article of interest 
in the same number is by Signor A. Piccone, on the part played 
by herbivorous (phytophagous) fishes in the distribution of marine 
alge, An examination of the intestines of several species of 
fish showed that, in addition to Zostera and other flowering 
plants, they contained the remains of a number of seaweeds, 
some of them in a fruiting condition, the spores of which are in 
all probability voided in the excrements, and are then in a 
favourable state for germination.—The remaining papers in 
these numbers are descriptive or contributions to local floras. 
