184 



HARD W1CKE 'S SCIENCE- G OSSIP. 



with what it is diluted, remains clear and transpar ent. 

 The ring can be put on the glass slip, the cell 

 cleaned, and be ready for use in a few minutes. I 

 strongly recommend it to the working micro scopist. 

 —John S. Hicks, F.R.C.S. 



VoLVOX Glo BATOR. — We strongly recommend 

 our readers to study an article in the Popular Science 

 Review for July, on "Volvox Globator," written by 

 Mr. A. W. Bennett, M.A., F.L.S. The same 

 journal also contains a capital paper by Dr. Wallich, 

 " On the Radiolaria as an order of the Protozoa." 



Microscopy in America. — It is proposed to hold 

 a Microscopical Congress in August next at Indian- 

 apolis, at which it is expected that all the leading 

 microscopical societies in the United States and 

 elsewhere will be represented. Perhaps this may be 

 the means of settling many of the vexed questions 

 with which journals devoted to microscopical re- 

 search are often too full. There is every expectation 

 of the meeting being successful, both in point of 

 numbers, and in the character of the papers to be 

 read. 



The Examination of Minute Living Organ- 

 isms. — Mr. Dudgeon suggests that living microsco- 

 pical objects might always be seen, if the objective 

 were enclosed in a brass or other metallic tube, 

 having its lower end closed by a piece of thin micro- 

 scopic glass coming close up but not touching the 

 object-glass. With this protection, he says, the end 

 of the microscope may be plunged into a small tank 

 filled with water, containing living organisms, and 

 thus the latter may be examined at leisure. 



ZOOLOGY, 



The Colouring Matter of Birds' Egg- 

 shells. — Mr. Liebermann has recently proved that 

 the blue or green colour of birds' eggs is due to a 

 bile pigment which resembles biliverdin in certain 

 respects. The shells frequently contain a second 

 colouring matter — not a bile pigment — which ex- 

 hibits a characteristic absorption spectrum. 



The Manatee at the Westminster Aqua- 

 rium. — Those who have the opportunity should 

 lose no time in seeing the Manatee (Mauatus Ameri- 

 canus) now on exhibition at the Westminster Aqua- 

 rium. This very individual might have been the one 

 which sat for its portrait in Science-Gossip for 

 March, 1876, so true is the illustration. Mr. South- 

 well's paper of the above date will be now read 

 with greater interest by those who visit the living 

 example. The latter was taken at the mouth of the 

 Essequibo, off the island of Leguan, British Guiana. 

 It was brought on the deck of the Blenheim to 

 Glasgow, where Mr. Carrington, the able naturalist of 

 the Westminster Aquarium, purchased it, on the 1st 



of July last, and brought it thence to London, in a 

 special truck. The greatest difficulty experienced in 

 its transit by railway was in keeping up the right 

 temperature, which is between 70" and 75 . When 

 the temperature was lower than 70 , the Manatee 

 would resent the reduction by raising itself bodily 

 upright out of its tank. The powerful muscles of 

 its enormous tail, and the extreme buoyancy of its 

 body, would easily enable the animal to do this. It is 

 healthy, eats about two stone weight of lettuces, 

 cabbages watercress, zostera, ulva, &e., every day ; 

 and sleeps in what seems a most uncomfortable 

 posture, arched like a half-bent bow, but still resting 

 on its tail. The last of its tribe as a denizen of 

 English waters was the Halitherinm of the Suffolk 

 Crags. 



Planorbis Nautileus (Crista). — I have been 

 fortunate enough to find the above minute shell upon 

 the Potamogeton in two ponds, not far from the Via- 

 duct, Folkestone. In one the specimens were more 

 numerous and finer than the other. It is the first 

 time this Planorbis has been found in this locality 



(July).-;* y. r. 



Habits of Raptorial Flies. — My attention 

 being attracted by a sharp buzzing on the window, I 

 looked, and saw two flies struggling together and 

 rolling over. After a very few moments one of them , 

 an Empis I think, flew away, leaving the other, a 

 common house-fly, alive, and apparently little the 

 worse. It walked about, and took a short flight, but 

 in less than half a minute it rolled over, became 

 convulsed, and died almost instantly after. Whether 

 its death was due to the abstraction of the blood, or 

 to the injection of a poison, I cannot say, but the 

 brief attack of the rapacious fly seemed certainly 

 more rapidly fatal than that of a moderate-sized 

 spider. — J. W. Slater. 



The Microphone in Natural History. — 

 Mr. S. D. Bairstow suggests the use of the micro- 

 phone for the investigation of the phenomenon of 

 stridulation in insects. 



Mimicry in Insects. — At a recent meeting of 

 the Entomological Society the photographs of two 

 species of Orthoptera, allied to Ptcrochroza illus- 

 Irata and P. ocellata were exhibited, in illustration 

 of the doctrine of "mimicry." The above insects 

 are remarkable for their perfect imitation of dead 

 leaves, which is carried out in the neuration of the 

 wings even to microscopic details, as compared with 

 the ribs and veining of leaves. 



Moles at Work. — Professor Paley, in a late 

 number of your periodical, says that he never met a 

 person who could aver having seen a molehill cast 

 up. I beg to state that moles have been at work 

 under my eyes on two occasions. So many years 

 have since passed, that I can only say, as to time, 



