(6 



SCIENCE-GOSSIP. 



[March ], 1866. 



that internal reflection is used for a purpose in the 

 transit instrument, it is true ; but, in fact, the cir- 

 cumstances are different. In the transit telescope a 

 reflector is placed at an angle of 45° with the axis 

 of the instrument, which receives a ray of light and 

 transmits it to the eye-piece for the purpose of 

 illuminating the views, across which the passage of 

 the star has to be noted. Further, this reflector is 

 of metal, and has a hole through its centre. It is, 

 in fact, annular or ring-shaped in form, so that it 

 does not at all interfere with the definition of the 

 rays passing through the object-glass. The forms 

 of internal reflectors, applied to the microscope 

 described in jour Journal, are open to the very grave 

 objection that, by interposing, at an angle, a refrac- 

 tive medium of greater or less thickness, they 

 destroyto a certain extent the corrections of the 

 objective. If the form employed in the transit were 

 really used (namely, an annular reflector), far more 

 satisfactory views would probably be obtained. — 

 IF. Hislop. 



Miniature Aquaria.— Those fond of the micro- 

 scope will find a large amount of entertainment and 

 opportunity for study in keeping a small aquarium 

 of salt water, made in the spring or summer. I 

 have two, — one in a large tumbler, the other in a 

 small glass jar. I stocked them at first from the 

 salt ditches near Yarmouth, and put in two or three 

 pieces of rock, with different sea-weeds growing on 

 them, with a few small snails. As the sea water 

 evaporates I fill up with fresh, and I am never in 

 want of abundant interesting objects, animal, vege- 

 table, diatomaceous, etc. In a drop I have often 

 counted some twenty or thirty interesting objects. 

 I keep them in a pretty good light, and sometimes 

 run the water from one to another by means of a 

 small glass-syphon, which only allows the water to 

 fall in drops.— R T. Scott. 



Illuminator for, High Power.— Since jotting 

 down the remarks in last number, I find it possible, 

 with a pair of Ross's " C " Kelner eye-pieces and 

 Powell & Lealaud's Illuminator, to use a T ' 5 with 

 the Binocular upon the Morpho Menelaus satis- 

 factorily. Sure it is that a small portion of the field 

 is obscured ; but a casual observer would certainly 

 not find it obtrusive, and it should be borne in 

 mind that with very high powers we must not 

 expect any very great depth of focus, and that a 

 mere point is all that can be reasonably expected to 

 be sharp at one time: still, I was somewhat sur- 

 prised in obtaining the results I did. One other 

 improvement I would mention : it consists in having 

 another stop fitted to the back of the illuminator, 

 limiting the rays to, say, £ of an inch ; this seems to 

 reduce the haze considerably : indeed, I cannot help 

 thinking that, if small back stops were fitted to the 

 object-glasses, we should hear little about " fog ;" 

 but microscopists generally are not satisfied unless 

 they hold the power of a large angular aperture in 



their hands, the same being quite under control by 

 the use of back stops. Before concluding, it should 

 be stated that the merit of first bringing this principle 

 of illumination to bear upon the microscope is 

 mainly due to Professor Smith, of Kenyou College, 

 in America. — /. Bockett. 



Influence of Study of Nature. — I have seen 

 the cultivated man, craving for travel and for suc- 

 cess in life, pent up in the drudgery of London 

 work, and yet keeping his spirit calm, and perhaps 

 his morals all the more righteous, by spending over 

 his microscope evenings which would too probably 

 have gradually been wasted at the theatre. I have 

 seen the young London beauty, amid all the excite- 

 ment and temptation of luxury and flattery, with 

 her heart pure and her mind occupied in a boudoir 

 full of shells and fossils, flowers and sea-weeds ; 

 keeping herself unspotted from the world, by con- 

 sidering the lilies of the field how they grow ; and 

 therefore it is that I hail with thankfulness every 

 fresh book of Natural History, as a fresh boon to 

 the young, a fresh help to those Avho have to educate 

 them. — Kingsleifs " Glaucus" 



The Honey Guide is an extraordinary bird. 

 Plow is it that every member of its family has 

 learned that all men, white or black, are fond of 

 honey ? The instant the little fellow gets a glimpse 

 of a man he hastens to greet him with the hearty 

 invitation to come — as Mbia translated it — tp a bee's 

 hive and take some honey. He .flies on in the 

 proper direction, perches on a tree, and looks back 

 to see if you are following him ; then on to another 

 and another, until he guides you to the spot. If 

 you do not accept his first invitation, he follows you 

 with pressing importunities, quite as anxious to lure 

 the stranger to the bees' hive as other birds are to 

 draw him away from their own nests. Except while 

 on the march, our men were sure to accept the in- 

 vitation, and manifested the same by a peculiar 

 responsive whistle, meaning, as they said, "All 

 right, go a-head, we are coming." The bird never 

 deceived them, but always guided them to a hive of 

 bees, though some had but little honey "In store. 

 Has this peculiar habit of the honey guide its origin, 

 as the attachment of dogs, in friendship for man, or 

 in love for the sweet pickings of the plunder left on 

 the ground ? — Livingstone's "Zambesi." 



British Lichens.— The Bcv. W. A. Leighton, 

 F.L.S., of Shrewsbury, has yielded to the repeated 

 solicitations of Dr. Wm. Nylander, of Paris, the 

 facile princeps of European Lichenologists, and is 

 engaged in preparing for publication a "Synopsis 

 of British Lichens." He will feel obliged by the 

 communications of notes of the localities of the rarer 

 species, and for specimens or intelligence of new 

 and undescribed lichens. 



