HARDWICKE'S SCIENCE-GOSSIP. 



i39 



At the Royal Institution, Professor Langley, of 

 the Alleghany University, Penn., recently delivered 

 a lecture on "Sunlight and its Absorption by the 

 Earth's Atmosphere." From a notice of it in the 

 " English Mechanic " it appears that he ascended one 

 of the peaks of the Alleghany Mountains in California, 

 and measured the heating effects of the different parts 

 of the spectrum at the bottom and at the top of the 

 mountain. At the top he found the ultra-red end 

 greatly elongated. The heating effects were presum- 

 ably observed by means of the bolometre, an instru- 

 ment which Professor Langley invented, finding that 

 the thermopile was not sufficiently sensitive. In the 

 bolometer, an exceedingly fine wire of platinum or 

 iron (he made one wire from a leaf of iron uoooth 

 of an inch in thickness), has its temperature and 

 hence its electrical conductivity changed in different 

 parts of the spectrum, the result being shown on a 

 very sensitive galvanometer. By means of a Row- 

 land's grating, the effect of twenty or thirty prisms 

 can be obtained without the squeezing together of the 

 red rays which is the result of using glass prisms. 



MICROSCOPY. 



. Cole's " Microscopical Studies." — Four slides, 

 illustrative of this series, are to hand, viz. Jaws of 

 Epeira Diadcma ; Batrachospermum ; Lung, alveolar 

 pneumonia, 3rd stage ; and a transverse section of the 

 organ of Bojanus from an Anodon. 



Type Slide of Blood. — Mr. Ernest Hinton also 

 sends a slide, showing in one mount the blood 

 corpuscles of man, frog, bird, fish and snake, a very 

 compact and instructive method of showing the 

 differences of type in the several kinds of blood 

 belonging to these different classes of vertebrate. 



Dry Mounting. — In mounting objects by the dry 

 process, a vapour condenses on the under side of the 

 thin glass cover, which, on evaporating, leaves a 

 series of small dots ; thus entirely spoiling the appear- 

 ance of the object under high powers. I may as well 

 state that my method of mounting is taken from 

 Martin's well-known manual, with the only difference 

 of using a thin layer of gum before I apply the gold- 

 bize. I shall be much obliged if any of your numerous 

 readers could give me any information on the subject. 

 — F. Cresrcuell Du Bois. 



Staining Nerve and Muscle. — I would refer 

 E. B. L. for directions for staining the above, and the 

 best modes of application, to read " Methods of 

 Research as used in the Zoological Station of Naples," 

 in vol. ii. of the "Postal Microscopical Journal," and 

 also " How to Work the Microscope," by Dr. Beale, 

 p. 299 (1868 ed.), &c, in which full details are 

 given for demonstration of finest fibres, &c. — V. A. 

 Latham. 



Liverpool Microscopical Society. — The 

 ordinary monthly meeting was held on Friday at the 

 Royal Institution, the President, Mr. Chas. Botterill, 

 F.R.M.S., in the chair, when there was a large 

 attendance. Mr. I. C. Thompson referred to the loss 

 sustained to microscopical science through the death 

 of Mr. Charles Vance Smith, who, though paralysed 

 for many years, had attained a high position amongst 

 microscopists through his delineation of the micro- 

 scopical structure of plants. Mr. A. Norman Tate, 

 F.I.C., read the paper of the evening, on "The 

 Microscopical Examination of Potable Water.*' 

 After alluding to the impossibility of always determin- 

 ing by chemical means alone, whether a water is 

 or is not fit for dietetic purposes, he proceeded to 

 speak of the importance of microscopical investigation 

 in relation to water supply, pointing out that it 

 afforded better opportunity of determining the 

 character of organic impurities, and that it might 

 frequently assist in ascertaining the character of the 

 mineral constituents. He described different modes 

 of collecting and examining waters microscopically, 

 and urged the importance of further investigation, so 

 as to ascertain how far the organised matters present 

 in water are capable of developing disease, and how 

 such organisms may be destroyed. In conclusion he 

 mentioned impurities found in natural ice, and also 

 two methods of examination of rain and air. A 

 discussion followed, and a conversazione was then 

 held at which a number of interesting objects were 

 exhibited. 



Boro-glyceride for mounting Micro-objects. 

 — During the past two years I have been experimenting 

 on this substance, and with, at present, such good 

 results, that it seems very worthy of extended trial. 

 Boro-glyceride is an antiseptic manufactured under 

 Professor BarfFs Patent by the Kreochyle Company. 

 It is non-poisonous and non-corrosive. Its two great 

 uses are for preserving food and for antiseptic dressing 

 for wounds. For mounting micro-objects, I use a 

 saturated solution, made by dissolving the substance 

 in warm water — using about one part to twelve of 

 water — and allowing the surplus to crystallise out and 

 settle. When it is known that this solution will 

 preserve white of egg without coagulating the 

 albumen, it will be seen to be very different in its 

 chemical action from such powerful antiseptics as 

 corrosive sublimate and carbolic acid. As far as my 

 observation goes, boro-glyceride solution is excellent 

 for vegetable tissues. It does not act on them in any 

 way, grains of chlorophyll even remain unchanged. 

 It does not destroy the aniline colours used for stain- 

 ing sections, although the delicate colours of flower 

 petals appear to bleach in the solution. It answers 

 for mounting insects whole and without pressure. 

 Gold size or brown cement does for fixing the upper 

 glass of the cell. The boro-glyceride, which is nearly 

 a new substance, having proved useful and easy of 



