SCIEiNTIFIC SUMMARY. 
439 
meteor, the greater part of which is now in the British Museum. The iron has 
an evidently porous structure, and the pores inclose a green silicate offering 
the crystallographic and optic characters of enstatite, and even its chemical 
composition according to the analysis of Professor Maskeleyne. 
The Physics of Tempering and Annealing. — At the meeting of the Aca- 
demy of Science (Paris), on August 2, M. Bichal read a paper on the 
variations which metals undergo as to density during the processes of tem- 
pering and annealing. The density of steel, which is 7*88, descends during 
tempering to 7-73, and ascends during annealing to 7*83. On being tem- 
pered again it descends to 7*73, and these phenomena may be repeated at 
will. On the other hand, the density of bronze is raised by tempering from 
8*8 to 8*9, and it descends in annealing to 8*7. 
Structure of Tin altered hy Cold. — At the Exeter meeting of the British 
Association, M. Eritsche (through Mr. Eoberts), communicated a paper on the 
change which block tin undergoes when exposed to intense cold. M. 
Eritsche found that the intense cold of St. Petersburg, during the winter of 
1867, caused solid blocks of tin to crumble and fall into pieces. That the 
change was due to intense cold was proved by submitting blocks of tin to a 
temperature of 40°C., when the same structure was induced. 
2'he Utilisation of Waste Gases from Blast Furnaces. — The blast furnace 
proprietors who have adopted one or other of the different methods employed 
for bringing down the gases report satisfactorily of the result. This, with 
regard to one plant of furnaces, is seen in the circumstance that between 250 
tons and 300 tons of fresh drawn slack, heretofore required in raising the 
steam for their blowing engines and for heating the blast, is now being 
offered for sale. The concern is that of the Parkfield Iron Company at 
Wolverhampton. 
Quantity of Copper produced in the Year 1866 over the Whole World. — The 
Chemical News, quoting from a recent paper by M. Petitgand, states that 
the quantity of this metal raised on the entire globe in the year alluded to 
— the latest period that statistical records of this kind have been reliably 
brought together— amounts to 93,415 tons, which is nearly double the 
quantity raised in 1846. From the statements made by this author, there 
appears to be an increasing tendency to a lower cost price of this metal. 
Large and valuable deposits of excellent copper ore known to exist, especially 
in Polynesia, are as yet untouched. 
MICKOSCOPY. 
Microscopical Me7noirs of the Quarter. — The following valuable contribu- 
tions to different departments of microscopical science have been published 
during July, August, and September in the pages of the Monthly Micro- 
scopical Journal : — 
On the Bectal Papillae of the Fly. By B. T. Lowne, M.B.C.S. — On the 
Diatom Prism, and the True Form of Diatom Markings. By the Eev. 
J. B. Eeade, M.A., F.E.S., President of the Eoyal jMicroscopical 
