HAflDWlCKE'S SCIENCE-GOSSIP. 



Ill 



tragacanth, the diatoms may be placed on this film, 

 and when arranged to tlie satisfaction of the 

 operator, may be fixed by being gently breathed 

 upon. After this the balsam may be applied with- 

 out any danger of disturbing the arrangement, and 

 the film of gum being transparent, becomes per- 

 fectly invisible. The breathing process, to soften 

 the gum, may be repeated as often as required, so 

 that each diatom may be fixed as soon as it is laid 

 in its place, and corrections may be made in the 

 grouping after the diatoms have been approxi- 

 mately arranged. With the same end in view, 

 some microscopists place a little gum in the water 

 in which the store of diatoms is contained ; but 

 this practice is objectionable, from the fact that the 

 gum coats the frustules and frequently prevents 

 the balsam from penetrating them ; thus damaging 

 or spoiling a slide which has taken a long time in 

 arranging. — F. W. M. 



Palates of Spiders. — I have been looking 

 through the back numbers of Science-Gossip, and 

 am surprised, in the paper on the alimentary system 

 of the Spider (June, 1868), to see so little notice 

 taken of what I consider a beautiful microscopical 

 object — the palate of the spider. The structure is 

 beautiful, and I am sure will repay the operator 

 for the little trouble it will take to dissect a spider 

 to obtain them. I would mention, that in many 

 of my insect dissections, to save time 1 apply car- 

 bolic acid and heat, and then Canada balsam, the 

 effect being that the acid renders them transparent, 

 and the balsam running in after, they can; be 

 mounted in a few minutes, where, by the soaking in 

 turps process, they would take hours or weeks. By 

 this plan the palates of the Spiders can be seen in 

 situ. — F. Barnard. 



Diatoms and Eoeaminipeea. — The following 

 process I have found the best for mounting the 

 latter in balsam. After arranging them (dry) on 

 the' slide, in the pattern desired, a drop of camphiue 

 should be applied to the slide, but not dropped 

 on the objects, as that would at once displace them. 

 The camphine will spread out, reach and become 

 absorbed by the forams. A gentle heat should 

 then be applied until the spirit has entirely evapo- 

 rated, when tlie forams will be found to be suffi- 

 ciently fixed on the glass to allow the usual 

 mounting process to be carried out. I have 

 usually applied and dried the camphine as described, 

 three or four times before mounting, in order to 

 prevent disappointment. Doubtless diatoms might 

 be mounted in a similar way, but of that I have no 

 experience. I should mention that I have always 

 used camphine with balsam, and find it equal to 

 anything else recommended.— (?. E. Ladbimj. 



Microscopic Postal Cabinets.— The following 

 is a scheme I wish to submit to the readers of 



Science-Gossip. Let a certain number of persons 

 living in different parts of the country, say twelve, 

 A, B, C, &c. &c., agree to form a postal cabinet 

 association, Avitli A as manager. A small entrance 

 fee and subscription (a shilling in each case 

 would probably be enough) would be paid by each 

 member to the manager, who would provide 

 a box capable of holding at least a dozen micro- 

 scopic slides, and which should be as light as is 

 consistent with the safety of its contents during its 

 transmission by post. A would then put into the 

 box an object likely to interest the other members, 

 and forward it by post to B, who, after examining 

 A's object, would add a slide of his o^;^^l, and for- 

 ward the box to C. C would add another slide, 

 and send it to D, and so on ; then when the box 

 arrives in the hands of L it contains eleven slides ; 

 he adds a twelfth, and returns -the box to A, who 

 takes out his own slide, replaces it by a new one, 

 and then sends it to the next member (B), who does 

 likewise. Thus, when each person receives the 

 cabinet, it contains eleven new slides and his own, 

 which he retains. It would of course be necessary 

 to have a code of rules, but they might be very 

 brief. The most important would be one limiting 

 the time each member could keep the box. With 

 twelve members it should make the circuit in a 

 month or five weeks. Two boxes might be estab- 

 lished, so that each member might receive a fresh 

 lot of objects about once a fortnight. I have bor- 

 rowed the above idea from the system of MS. 

 magazines, which has been adopted for many years 

 by persons who use Pitman's phonetic shorthand. 

 A further advantage would arise to the members of 

 such an association as I have proposed, if each 

 member were allowed to make brief notes as to his 

 own object, or those of the other members. — Alfred 

 Atkinson. 



ZOOLOGY. 



Appearance of the Cambeewell Beauty. — 

 During the past week two specimens of the 

 Camberwell Beauty {Vanessa Antiopa) have 

 been observed on the banks of the river Dee, 

 Aberdeenshire. — Wilcehe. 



Man and Apes. — This is the title of the first of 

 two articles by St. George Mivart, E.R.S.,' the 

 well-known author of the " Genesis of Species," 

 which appears in the last number of the Popular 

 Science Review. It is copiously illustrated, and sets 

 forth in a clear and distinct manner the affinities 

 and distinctions of the leading groups of the Qua- 

 drumana. 



Wild Birds' Protection Act. — The following 

 is the schedule of wild birds protected by the above 

 Act, and to knowingly kill, take, or wound any of 



