2 54 



SCIENCE- GOSSIP. 



the operator to readily exchange the lenses. The 

 same object can be attained by having adapting 

 rings or flanges to screw one into the other. 



VII. TURNTABLE. — This is a rather modern 

 addition to the camera, and is very convenient, as 

 it dispenses with the tripod top and screw. The 

 tripod legs are fitted on to the camera by its 

 means, and it also allows the camera to be turned 

 in any direction. 



VIII. Double Dark Slides, or Plate- 

 holders. — There are two forms of slides in the 

 market, one called the book form, and the other 

 solid or shut off. Of these two we much prefer 

 the book form, as it is more convenient in use, and 

 as a rule better made than the shut-off type. It is 

 a matter of absolute necessity that the dark slide 

 should be light-tight, and this is more readily 

 secured in the book form than in the shut-off. 

 We consider it advisable to have at least three 

 double slides to the camera, thus carrying six 

 plates, two in each slide. 



IX. Tripod. — This is the stand upon which 

 the camera is erected. The legs are made in 

 many forms, but whatever style is selected, we 



2. Camera with Square Bellows-. 



w T ould strongly impress upon the beginner to 

 choose one that is perfectly rigid. The three-fold 

 stand is, we think, the most convenient, as it folds 

 up fairly small, and can be had in conjunction 

 with great rigidity. In most three-fold stands the 

 bottom portion of the leg is made to slide, which 

 will be found very useful in working on uneven 

 ground, and also for lowering the camera. Fig. 1 

 show T s a drawing of a type of camera containing 

 all the movements we recommend, which are 

 found the most convenient style for the average 

 amateur. It is light, and folds into a small space, 

 being easily carried and readily erected. There is, 

 however, another good form of camera which we 

 advise, where weight is not so much an object as 

 extreme rigidity. This camera is generally re- 

 ferred to as the square-bellows type, and is perhaps 

 the more useful all-round camera of the two. It 

 can also be readily adapted for stereoscopic photo- 

 graphy. If it is proposed to take up this most 

 interesting branch of photography, we recommend 

 the student to start with a 7| in. x 5 in. camera, as 

 it is a most convenient size and lends itself readily 

 to adaptation for stereoscopic work, the stereo- 

 scopic plate being 3^ in. x 6f in. Although we 

 recommend this, size where possible, yet the half- 

 plate camera can be used for stereoscopic photo- 

 graphy, and the view may be taken on an ordinary 

 half-plate. We shall touch upon the various re- 

 quirements for this purpose under a future section. 

 Fig. 2 illustrates this square type of instrument. 

 (To be continued.') 



Green Elder-fruit. — The Rev. C. F. Thornewill 

 will be interested to know that there is a bush of 

 the green-fruited elder in this parish ; also that I 

 remember seeing when a boy bushes of it — one 

 near Wrottesley Park, and another at Tettenhall, 

 both in the neighbourhood of Wolverhampton. — 

 (Rev.) K. A. Dealtin, Co/ton Hacltett, Worcester- 

 shire. 



Green Variety of Elder-fruit. — The green- 

 fruited elder which the Rev. Mr. Thornewill had 

 sent him by the lady of North Derbyshire is not 

 at all an uncommon plant in this neighbourhood. 

 Those who are thoroughly familiar with the variety 

 find little difficulty in distinguishing it from the 

 dark- fruited and commoner sort, even in winter 

 time. It usually grows more compact, is lighter 

 coloured where the old bark begins to rend, and 

 the buds show a much brighter and more lively 

 green when they begin to expand. Botanically it 

 is regarded only as a variety of the commoner form. 

 — John Wilson, Leazes Park, Nemcastle-on-Tyne, of 

 Sambucus nigra. 



The Mild Autumn. — It may interest your 

 readers to know that on October 21st, at Pirton, 

 near Hitchin. I picked several wild roses in full 

 bloom and with buds. On the 25th of the same 

 month I took 111 larvae of Bombyx ritbi, and could 

 have taken nearly as man]' again ; they were feed- 

 ing in the sunshine on grass and plantain. On 

 the same day I picked two fine pieces of honey- 

 suckle in bloom, a very late date for this shrub 

 to flower. — Fredk. Jas. Bridgman, " Kenmore" 

 Avenue Road, High gate, N. 



Relation of Parent to Offspring. — In his 

 interesting paper on "Parental Relationship" in 

 the November number of Science-Gossip, Mr. 

 Leighton remarks that in the amphibians " the 

 relation of parent to offspring may be said to be 

 non-existent, the same applying to the fishes, and 

 we look in vain for any sign of it lower in nature." 

 May I be permitted to remind him that signs of 

 the relationship are to be found well marked in 

 some insects — e.g. the common earwig, the female 

 of which sits on her eggs and young, and looks 

 after them as well as does any hen-bird ? Again, 

 amongst spiders the females of many species watch 

 and even carry about with them the sac containing 

 their eggs, and when the young are hatched feed 

 them till they are able to fend for themselves. 

 Amongst fishes, again, the common stickleback is 

 a well-marked example of the existence of parental 

 care. In the case of this fish it is the male who is 

 the nurse. A most interesting account of the 

 labours of papa stickleback may be found in a 

 paper by the late Mr. Grant Allen which appeared 

 in the " Strand Magazine " for May 1899. In the 

 same article he refers to the parental duties as 

 carried out b^y the tube-mouth fish, the pipe-fish, 

 and some amphibians and reptiles. — Albert May, 

 Hagling Island. 



