SCIENTIFIC SUMMARY. 
255 
trived a press in wKicli the pumps are suppressed. For this purpose the 
press is provided with a hobhin in the rani chamber, into which a catgut band 
can be coiled ; this cato-nt band dravTi mto the chamber through a stuffing- 
box, acts in the saijie way as the fluid pumped in in the ordinary press. The 
ram chamber is filled with oil. 
Influence of Changes of Loads on Wrought Iron Structures. — Mr. Fairbairn 
has communicated to the Eoyal Society the results of his experiments on the 
efiects of continued changes of load and ■\dbration on girders and bridges. A 
wrought-iron plate girder wa» arranged so that a definite weight, representing 
a railway train or other moving load, could be placed upon it, removed and 
replaced successively, the number of changes bemg registered. Under these 
conditions the beam sustained 596,790 changes of a load equivalent to one- 
fourth the breaking weight, and 403,210 changes of a load equal to two- 
sevenths of the breaking weight. It then broke after 5,175 changes of a 
load equal to two-fifths of the breaking weight. After being repaired the 
experiments were repeated, and the beam sustained 3,150,000 changes of a 
load equivalent to one-fourth the breaking weight, and broke after 313,000 
changes of a load equal to one-third of the breaking weight. The tensile 
strain on the bottom flange, allowing for the metal punched out for rivets, 
was, in the first trials, 6‘25 tons, 7*39 tons, and 9*88 tons respectively, and in 
the latter trials 6*25 tons and 8*45 tons respectively. From these experi- 
ments Mr. Fairbairn infers that a wrought-iron bridge would be safe for a 
long series of years, with a straui of 6 tons joer square mch, or one-fourth the 
statical breaking weight. It is, however, evident that time is an element in 
the resisting powers of materials of every description under changmg loads. 
MICKOSCOPY. 
Notices of additions to science, which some would arrange under the above 
head, may be found in the followmg sections : — 
Botany — • 
New British Lichens. 
The Development of Composite Flowers. 
Eaphides as Diagnostic Characters of Plants. 
Importance o.f studying Development of Algse. 
Medical Science — 
The Structure of the Cerebellum. 
The Eetina of the Whale. 
The Malpighian Tufts of the Kidney. 
The Moveable Corpuscles of the Cornea. 
Blue Matter in Pus. 
Zoology — 
Are Vibriones Anmials ? 
Peculiar Structures in the Seminal Fluid of lantliina. 
Termination of Nerves in Muscles of Insects. 
The Circulation in the Vorticellidse. 
Little has been done during the past quarter hi the manufacture of 
new forms of instruments, and this result, we apprehend, is attributable to 
