112 



HARDWICKE'S SC 1ENCE - GOSSIP. 



auy tube may be taken out, and the spiders them- 

 selves removed from the tube without injury or 

 difficulty, and as easily replaced. It is only neces- 

 sary to use a pair of fine pliers with which to handle 

 the specimens, and a pair of longer and larger ones, 

 with oval cork or silk-padded points, with which to 

 put in the tubes or remove them from the bottles. 

 The label with the spider's name on it can be easily 

 read through both the tube and bottle, if put in so 

 as to coil closely round the inside of the former, 

 which is, with very little practice, a simple matter 

 to effect. The advantage of having the label inside 

 is obvious ; for it cannot then be rubbed off by 

 external friction, and it can be removed and replaced 

 at pleasure. 



After many trials of different ways of managing 

 test-tubes of spirit in which spiders have been 

 placed, I can at last pronounce the above plan 

 to be almost entirely satisfactory. When stopped 

 with corks, and laid or kept upright in drawers, the 

 spirit was quickly and constantly evaporating, 

 requiring frequent refilling ; besides which, the corks 

 soon became rotten with the action of the spirit, and 

 not only allowed that in the tube to evaporate, but 

 also, often breaking in removal, caused considerable 

 trouble, and sometimes damage to the specimens, 

 in getting out the portion left in the tube. Another 

 evil has also vanished by the use of wool pledgets 

 instead of corks, and that is the occasionally serious 

 cuts to the fingers from the sudden breakage of the 

 tubes in corking. As the greater part of my own 

 collection is intended for purely scientific purposes, 

 I only take the trouble to set out here and there a 

 specimen for the delectation of unscientific friends ; 

 for when set out, they occupy, of course, far more 

 space in a tube than when put in just as they happen 

 to come out from the effects of the chloroform, or 

 other stupefying agent. A single tube will often 

 thus contain up to twenty or more examples unset, 

 but never more than one species in a tube, and often 

 only one sex. In all cases the name of the species, 

 or a number written on parchment, should^be placed 

 in each tube, as above described. Glass-stoppered 

 bottles, containing inverted wool-stopped tubes, 

 of unset spiders, may be filled quite full of the tubes, 

 since there is no .object in merely ranging them 

 round next to the glass, as recommended when the 

 spiders are set out in a natural posture ; any tube 

 must therefore, in this case, be taken oat before the 

 contents can be examined. The numbers and names, 

 however, of the spiders contained in the bottle, are 

 known at a glauce, by being written at length on a 

 paper and gummed upon one side of the bottle, and 

 so, being turned outwards on the shelf, it is legible 

 without any necessity of handling. The sizes of 

 the test-tubes and outer bottles required will vary. 

 I am now using (and finding more handy and con- 

 venient than any others of the latter) strong wide- 

 mouthed phials (corked, but, of course, glass-stop- 



pered ones would be preferable, though much more 

 costly) of the following sizes:— i oz., loz., 2 oz., 

 and 4 oz. : these are kept in stock by most chemists' 

 bottle-dealers, and may be had at a very reasonable 

 price. The tubes vary from an inch and a half long, 

 and of the size of a large straw mote, to three 

 inches long, and not too large to go into the mouths 

 of the 2 and 4 oz. bottles, but large enough to con- 

 tain the largest tropical spiders, except the com- 

 paratively few giants of the families Theraphosides, 

 Thomisides, and Epe'irides : these may be put into 

 the bottles without the intervention of any tube. 

 When thus preserved, and arranged on narrow 

 shelves, according to their systematic position, a 

 collection of spiders is by no means an unsightly 

 object, and its contents are almost as easily got at 

 for reference and examination as the contents of most 

 insect cabinets. 



MICROSCOPY. 



"Silicious Substances found in Portland 

 Stone." — At a recent meeting of the Norwich 

 Geological Society, Mr. F. Kitton read a paper on 

 this subject, and exhibited some beautiful micro- 

 scopic sections, with those of carboniferous Oolite, 

 sandstone (India), silicified Oolitic limestone (Port- 

 land), and flint, showing sponge spicules, agate, &c. 

 On examination of the specimen (Portland stone) 

 presented to his notice, said to contain flint, Mr. 

 Kitton remarked, that it did not contain true flint, 

 not being nodular, nor exhibiting .the conchoidal 

 fracture when broken. It was doubly refractive, and 

 its distinct crystalline character was shown, in this 

 respect resembling the agates and porphyries. The 

 microscope revealed no trace of organic remains, so 

 common to true flints. The non-silicified portion of 

 the stone was composed of the usual little calcareous 

 bodies, which were formerly supposed to consist of 

 the remains of organized bodies of a globular form, 

 like the roe of fishes. Mr. Kitton further observed 

 of the Oolites, of which he showed sections, that 

 they formed no small part of the strata of this 

 island, being supposed to form a zone of some 30 

 miles broad in England, divided into Upper, Middle, 

 and Lower Oolite, and rich in fossil remains, these 

 spherical concretions varying in size from a small 

 pin's-head to a small pea : the latter is known under 

 the name of Pisolite, differing from true Oolite only 

 in the size of the globules. The silicified Oolite 

 differed from flint found in chalk in its gradual 

 silicification, whilst in the latter the segregation 

 of silicic acid is complete. No portion of the 

 silicified part of the specimen before him was equal 

 to the flint in hardness, it not exceeding in that re- 

 spect common granites. He offered the following 

 explanation as seeming the most feasible in ac- 

 counting for the silicification of the portion of the 



