SCIENCE-GOSSIP. 





MICIt» (SI i IP\ I i IR Bl GINNERS. 

 Hi f Sim LiNiiTO S -i i i I- R. M.S 

 ■ ■ ■ page 88.) 



■ i hi tion in detail 



must be the " I "" ! " I dii mds ol 



\i i . \\ , H ;h I lolborn. The 



I i : iiul is quite .1 new model. It is on a 



i idju ilnienl by 



rack and pi ami a particular!) sensitive 



Iteady I I hi n i ■ al io a draw- 



rom iv to 250 mm., fitting for sub- 

 ipparatus ind so arrani 



to swing out ol ili' when desired, also the 



usual mirrors. With one eye-piece, inch and 

 objectives, Abbe illuminator, with iris diaphragm, stop 



ni'l ' arrii 1 i" ""I mahoganj 1 1 n c 



plete, thi 'M The stand alone, with one 



y, piece, costs 1 



Tin, firm's " I dinburgh" stand is one concerning 

 which we can spea] highly from personal knowledge, 

 and it is capable 

 .! aim ' • 

 work of original 

 research. Ii is 

 ;i larger stand 

 than the 

 going, and is 



. but the 

 "G" model, 

 with rack and 

 pinion focussing 

 sub-stage, in 

 addition to the 

 requi r e mi' 111 1 

 111 entioned 

 above, would 

 osi .{."12. 



We cannot, 

 for w a n 1 I 



, mention 

 in detail the 

 standsofMessi s. 

 Baker, Collins, 

 Crouch, New 

 ton, etc., in 

 Engla ml . 1 

 those of Zeiss, 

 Leitz, Reichert, 

 1 1 1 ' 1 s c li and 



etc., abroad. We may be pardoned if 

 we express here our opinion, formed by practical 

 observation, that the best English stands are, on 

 the whole, preferable to those of Continental make. 

 W iic aware that this statement runs counter 

 1 ■ the beliel ol too many science teachers, but it will 

 ■ supported b) the opinion of those whose work 

 makesil necessary for them to use the microscope as 

 more than a mere magnifying glass. Even now, 

 when the English condenser has become so universal, 

 we see mil 1 ireign opticians of repute sold 



without condenser fittings, and even without a joint 

 by which the microscope can be inclined at will, 

 while the stand has invariably the horse-shoi 

 with a more or less lop heavy stage above it. 



We have purposely given example-- and quoted 

 prices of microscopes fitted with all the essentials 

 enumerated in our preceding papers, because they are 

 ii' ISO ipe. I If course, money 

 may be sued by buying, for instance, a 

 microscope withoul 1 condenser, as in the pretentious 

 stands one meets in every other optician's window : 

 but it 1 to save the beginner from the mistake of 



M [( ROSCOPE 



making uses that th mainly 



Keeping in view al to obtain a 



d that I work, we 



I as are the 



tically 

 binocular itself can only be 

 es up to aboi 

 a 1 ' aii ti 



1 . we have nol 

 tioned n I -mges, though most of the 



going mi 1 I be fitted with them. They 



ai : ' ential foi 



work. A small sliding stage, however, costing 

 tos, upwards, is well worth ti ; 



I laving selected our stand, il now ' 



to ipeal il the s. The improvement in these 



.! late yeai 1 has I ecu em irroou 1 or 1 

 sum the mil roscopisl can tives with a 



definition that leaves hut little to be desired. As we 

 wish to keep entirely free from technicalities, we will 

 nol go into the difference between apochromati 



further than to ly, thai the former, if 

 genuine, are quite tree from all outstanding 1 

 and give unsurpassed definition, whilst thi 

 h ' piecing more satisfactorily than the 



matics. < In the other hand, their price is prohibitive 

 I., mosi students, a ,'An.oil immersion bj / 



£'S t" /•-• 



ling to ii s 



aperture. The 



reader may resi 



red that 



roma- 



■ first-class 



makers, will 



show him almost 



all that the 



is 



capableof reveal- 

 ing, and we 



mention 



Really not 



a few achro- 



matics by indi- 

 vidual makers 

 whose perform- 

 ance on really 

 critical tests 

 compares very 

 closely indeed 

 with that of the apochromatics. The selection of the 

 objectives is, however, a most important matter, and 

 the advice of a really competent friend is invaluable. 

 Certain makers are well known for objectives of certain 

 powers, and we strongly recommend the beginner to 

 get his objectives only from the very foremost makers. 

 The best all-round objective for the beginner is the 

 inch, after thai the [in. or .'.in. — the former for 

 preference for botanical work, the latter for human 

 igy. As the worker becomes further advanced 

 he will wish to add others. The 2in. is a 1110-1 

 useful lens, as it takes in a large field, the 

 .Un. comes in between the I in. and the Jan., 

 and an !in. (dry) is useful in certain circum- 

 stances. Any higher power than this should be 

 an "immersion" lens, either water or oil, and the 

 mos' frequently met with is a ,' ; in. oil immersion. 

 But the beginner is not advised to gel really high 

 powers until he actually requires them, lie will find 

 that mere magnification is by no means the main 

 object in microscopical work, and that the real worker 

 invariably uses the lowesl possible power. 

 ' To *V continued,) 





Edinbi rgh Students 



Microsi 



