i86 



SCIENCE- G OSSIP. 



MICROSCOPY FOE BEGINNERS. 



By F. Shilltxgtox Scales, F.R.M.S. 



{Continued from p. 154.) 



Ix using glycerine mounting media it is well 

 to remember, as pointed out by Dr. Carpenter, 

 that they largely increase the transparency of 

 organic substances : and though this is often ad- 

 vantageous, it may also sometimes result in so 

 great a diminution of their reflecting capacity as 

 to make them indifferent mounts. We have given 

 such instructions in elementary mounting as will, 

 we think, enable a beginner to make rapid progress 

 in the art if he is gifted with only a small amount 

 of perseverance and patience, but it must not be 

 forgotten that the actual mounting is but a part of 

 the work required. Numerous subjects will need 

 very careful preparation beforehand, and on the 

 methods adopted and the skill and judgment with 

 which they are carried out will depend much of 

 the result. Many objects will need dissecting. In 

 one of our previous papers (Sctenxe-Gosslp, 

 vol. vi.. pp. 280-1) we gave a description of a 

 home-made dissecting stand with supports for the 

 hands, and of the necessary apparatus for the pur- 

 pose. Their uses are self-evident. We may say here, 

 however, that most dissections, and especially 

 delicate dissections, are done under water, with 

 perhaps a little methylated spirit added if the 

 object has previously been soaking for some time 

 in methylated spirit or alcohol. In some cases it 

 will be necessary to fasten the object down, and 

 this may be done with pins on a weighted piece 

 of cork placed inside the dissecting dish, or by 

 running paraffin or some such compound into the 

 bottom as already explained. Watchglasses with 

 flat bottoms make useful dissecting dishes. Two 

 or three needles set in light wooden handles will 

 be required, with both straight and bent points. 

 and these can readily be manufactured at home, or 

 purchased for a few pence. In buying dissecting 

 knives, we strongly recommend that those with 

 ivory handles be chosen: they only cost one 

 shilling and ninepence each, as against eighteen- 

 pence for the ebony -handled ones, while the latter 

 are so brittle as to break with very little pressure. 

 There are a good many shapes of blades sold, but 

 perhaps the most generally useful are the usual 

 scalpel forms, the spear, and the spatulate-shaped 

 ones. Forceps may be either steel, brass, or nickel, 

 but we prefer the steel, which should, of course, 

 be carefully kept clear of rust. A few camel-hair 

 brushes are also necessary, and a pair of fine 

 scissors. Insects generally require soaking in a 

 ten per cent, solution of sodium or potassium 

 hydrate (caustic potash), for periods varying from 

 an hour or two up to a week. Too much soaking 

 will destroy the object and also render it too 

 transparent after mounting, whilst too little may 

 leave it hard and difficult to deal with. A little 

 thought and attention will therefore be necessary, 

 and a slight pressure with a blunt needle will tell 

 whether the object is sufficiently soaked. In the 

 case of large insects, like cockroaches, we should 

 soak them for several days until they begin to 

 give off an unpleasant smell. The alkali must then 

 be removed by soaking in several changes of clean 

 water. The inside of the insect can be got rid of 

 by gentle treatment with the camel-hair brushes. 

 Plant subjects are best softened by long soaking in 

 water. 



(To be continued.') 



CONDLCTED BY EDWARD A. MARTIN, F.G.S. 



By the resignation of the chair of geology at 

 University College, London, so long held by the 

 Eev. Thomas George Bonney. D.Sc, LL.D.. F.R.S., 

 a scientific prize will fall to someone after Christ- 

 mas nest. Professor Bonney. who is Hon. Canon 

 of Manchester and Fellow of St. John's College, 

 Cambridge, has held the professorship he will so 

 soon vacate for upwards of twenty years. He was 

 born at Rugeley in 1833. 



Some Deep Loxdox Borl\~C4S. — The following 

 particulars of borings in London, which have been 

 made into the Chalk, are in continuation of those 

 given in the July number of Science-Gossip. The 

 same remarks there made will now apply, and the 

 depths there assigned to the ever-changing Terti- 

 aries may be liable to future correction. For these 

 details I am again indebted to Messrs. Isler & Co., 

 the well-known well-sinkers of Southwark : — 



Place ot Boring ** J 3 



I- s n 



I a 



5 T3 <3 



5 3 £ 



& :1 st £ w 



Clapham Road. ft. ft. 



139 (Causton) 28 77 

 Croydon (Steam 



Laundry) .... 19 47 

 Forest Gate 



(Lpton Lane) 28 25 

 Grav's Inn Road 



(Perkins) 12 56 



Great Dover St.. 



S.E. (Groves) 49 — 

 Hackney Road 



(Chandler).... 12* 40J 

 London Bridge 



(Hibemia 



Chambers) 21 

 Hornsey Road 



(Baths) 



Lambeth (Dann 



& Valentine; . . 31* 90* 

 Latimer Rd.. W. 



(Phoenix 



Brewery) 22 126 

 Mitcham — 



(Camwal) .... — — 

 Mitcham — 



(Gas Works) . . 148* 22 

 Alitcham — 



(Thunder & 



Little) 26 67 

 Nine Elms— 



(Thorne) 22 — 



Peckham — 



( Rye Lane ) .... 23 2 

 Regent's Park — 



(Zoo) 178 — 



Romford Road. 



,242). E 22 — 



Rotherhithe St. 



1 251 > 117 — 



Waddon — 



i Croydon) .... 4 — 



ft. 



47* 



ft. ft. ft. 

 38 230 425 



12,000 



ft. 

 54 



36 



57 75 250 



1,000 



66 



23 



29* 144* 250 



2,34(1 



27 



57 



28 147 300 



3,000 



— 



62 



39 129 279 





60 



77 



17 253 400 



10.000 



93 



77 — 441 56 101*300 1,000 95 



1*104* — 28J 572 258 450 10.000165 i 



I 



1 49*, 43*. 105 320 4,000; 81 



52 22 178 400 4,500 80 



— — 333 333 1,000 19 | 

 38* 30^118£350 3,500 20 



39 39 174 340 2,000 — 



151* 39 139 351 1,500 54 



18J 30* 33 124 1,000 40 



23 12 239 452 8,000 — I 



27 44 146 250 4,200 30 | 



— 7 139 263 j 2,580 45 j 



— — "296 300 10,000 42§ : 



