458 
RECENT SCIENTIFIC INTELLIGENCE. 
more strongly in proportion, as it is separated 
or disengaged from the other ; and in gene- 
ral, we may say, that the magnetic power, 
produced by a discharge of the Leyden jar, 
is only the effect determined by the simulta- 
neous union of two magnetizing, more or less 
unequal and opposed, forces. 7. The com- 
mon simple spark of the machine produces 
analogous phenomena. — lbid» 
NOTICE RESPECT ING DR. EHREN- 
BERG’S COLLECTIONS OF DRIED 
INFUSORIA, AND OTHER MICRO- 
SCOPIC OBJECTS. 
To Richard Taylor, Esq.., &c. &c. 
British Museum, 21st Jnne,1836. 
Dear Sir, 
DR. EHRENBERG of Berlin, well 
known for his elaborate work on the Infuso- 
ria*, has recently presented to the British 
Museum a series of dried microscopic objects, 
consisting chiefly of infusory animalcules, 
globules of blood, &C', accompanied by a short 
notice (too shoit indeed) of his method of pre- 
paring them, and a list of the subjects. Dr. 
Ehrenberg preserves these most minute and pe- 
rishable of known organic formsby meansof ra- 
pid desiccation on little plates of mica, in winch 
manner he informs us that he has succeeded in 
making a very satisfactory dried collection, 
not only of nearly 300 species of Infusoria, 
but also of other kinds of microscopic objects. 
He mounts them betwen double plates of mica, 
fixed in the cells of slides, in the usual manner 
of preparing the scales of butterflies and Po- 
durce, and other transparent microscopic ob- 
jects ; and thus, he says, “ I have not only 
preserved the form and colour of the shielded 
(cuirasses ) Rotatoria and Bacillaria, but al- 
so the softest and most delicate o( the polygas- 
tiic Infusoria, even these of the genus Monas ; 
as well as the tissue of plants ; the Spermato- 
zoa. and CercaricB ; the different sorts of glo- 
bules of blood, with their nuclei; globules 
of lymph, chyle, and milk; and the nervous 
tubes, &c., of a great number of animals, and 
of man.” 
A power of about 3o0 (linear) is sufficient 
for viewing these objects, “ but a lower power 
does not show them satisfactorily, however 
well they may be illuminated ” 
I subjoin a list of the subjects presented to 
the Museum, and remain, 
Dear Sir, faithfully yours, 
John Geo. Children. 
Slide^ No. 1- 
1. Monas viridis- 
2. Polysoma uvella, and Monas termo. 
3. Spirillum undula, and Vibrio bacillus. 
4- Euglenia acus; Eu. viridis ; Eu- pyrum* 
5“ Coleps hirsutus.. 
6‘ Volvox globator. 
No. 2. 
1. Paramecium caudatuin. 
2. Glaucoma scintillans. 
3. Trichoda carnium. 
4. Charchesium polypinum. 
5' Epistyli-s nutans. 
6. Euplotes Charon. 
No. 3. 
1. Stentor niger. 
2. Paramecium aurelia. 
3. Glaucoma scintillans. 
4. Stentor polymorphus. 
5. Stentor coeruleu-. 
6. Idem— compressed, to show the testiculi. 
No, 4. 
1* Nassula ornata. 
2. Nassula elegans. 
3. Nassula aurea. 
4. Idem— Cl ushed, to show the teeth. 
5. Chilodon uncinatus. 
6. Chlamydomonas pulvisculus. 
No. 5. 
1. Hydatina senta. 
2. Idem — crushed, to show the teeth, 
3. Polyarthra trigla. 
4. Brachionus pala—with its eggs. 
5. Brachionus rubens — ditto. 
6. Anuraea aculeata. 
No. 6. 
1. Globules of blood of the Sheep (Ovis aries). 
2. Ditto of the Frog (Rana temporaria). 
3. Grains of the Retina of the Eye of the same. 
4. Spermatozoa vespertilionis murini. 
5. Arhnanthes longipes. 
6. Meridion vernale ; Fragilaria rhabdosoma ; 
Navicula acus ; Na. amphisbaina. 
Philosophical Magazine, August, 1836, 
EHRENBERG’S NEW DISCOVERY 
IN PALAEONTOLOGY : 
TRIPOLI COMPOSED WHOLLY OF INFUSORIAL 
exuvive 
At the sitting of the Royal Academy of 
of Sciences of Paris, July 11th, the following 
letter was communicated, dated Berlin the 
3rd of July, from M. Alexander Brongniart: 
— ‘‘I have today become acquainted with a 
discovery entirely new, for which we are in- 
debted to M. Ehrenberg, and which he has 
demonstrated to me in the clearest manner ; 
it is that the rocks of homogeneous appearance 
which are not very hard, friable, even fissile, 
entirely formed ofsiiex, and which are known 
by the names of tripoli, more or less solid 
(PoUerschiefer of Werner), are entirely com- 
posed of the exuviae or rather of the perfectly 
ascertained skeletons of infusorial animals of 
the family of the Bacillaria and of the genera 
Cocconema, Gomphonema, Synedra, Gaillo- 
nelLa, &c. These remains having perfectly 
preserved the forms of the siliceous carcases 
of these infusoria, may be seen with the great- 
est clearnsss through the microscope, and may 
easily be compared with living species, observ- 
ed and accurately drawn by M. Ehrenberg. 
