412 



NATURE 



[Januar- 



)I 2 



Memories of a School Inspector. Thirty'five Years in 



Lancashire and Suffolk. By A. J. Swinburnr, 



Pp. 274. (Snape Priory, Saxmundham : PublishocI 



by the Author; London: M'Dougall, n.d.) Pricf 



2s. 6d. net. 



This story of thirty-five years' work as a Government 



inspector of elementary schools is concerned chiefly 



with anecdotes of encounters with a f^reat variety of 



characters. Educational questions of importance arc 



touched upon lightly here and there, but the object 



of the book appears to provide entertaining,' reading 



for leisure hours. 



when compared with the Engliih tripod. Itbtrur th.ntt? 

 an- thn-e pt)ints of Mippon, but tlwy are fi' 

 far apnrt, nnd urf not in rh<» position in n 

 crnfrr <>f . " ' ' iin. s, 



(Kisitinii. 'signed 



.1 ;.( ,, ,1 il... 



LETTERS TO THE EDITOR. 



[The Editor docs not hold himself responsible for opinions 

 expressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the -writers of, rejected 

 manuscripts intended for this or any other part of Nature. 

 So notice is taken of anonymous communications.] 



Microscope Stands. 



MlCROSCOPiSTS will have experienced a feeling of satis- 

 faction that, what they might anticipate would be a care- 

 fully reasoned consideration of the respective merits of 

 Continental and Elnglish microscopes, had been provided 

 for them in the issue of Nature of December 21 last, but 

 their satisfaction must have been considerably modified 

 when they had finished reading the article in question. The 

 subject is admittedly one of considerable difficulty, but no 

 good purpose is to be served by giving the opinions of 

 those, if one may judge from the opinions expressed, who 

 are only able to see from the point of view of the producer, 

 the user not being considered. Apparently the intention is 

 to state the matter from each side : the first and second 

 sections, therefore, treat of the characteristics and 

 advantages of the English and Continental types re- 

 spectively, while the third and concluding section would 

 presumably be a careful comparison of these two types. 

 In point of fact, the latter is nothing but a eulofiy of the 

 productions of Continental houses, and, if the concluding 

 sentence is to be accepted, there is nothing left for English 

 producers but to retire from the field and leave them in 

 undisputed possession. 



The opening statement of the claims for superiority in 

 the English stand is fairly set out ; in fact, as no particular 

 opinion is expressed on the merits or demerits of this type 

 of instrument other than to indicate its good points, little 

 can be urged against it. The controversial part is mainly 

 confined to that in which the provision of sprung bearings 

 and controlling screws is set forth as an advantage, but I 

 shall have occasion to refer to this further when considering 

 the claims of the Continental type. 



The second part of the article is headed " A Defence of 

 the Continental Form." The first point raised, that the 

 short Continental microscopes are more convenient in use, 

 applies only when the instrument is used in a vertical 

 position : but it should have been pointed out that this 

 shortness is dependent on the optical tube length, which 

 is shorter than in the English type. 



The mechanical stages on the best Continental stands 

 are all that could be wished, and the claims made under 

 that head are quite justifiable. 



The substage arrangements might easily be the subject 

 of criticism, as in most Continental types they are far too 

 cramped, and there is not sufficient latitude to allow of the 

 easy manipulation of the various substage fittings. At 

 the same time it must be admitted that in all but a very 

 few cases a fine adjustment motion to the substage fittings 

 is not necessary. But this is not because the Continental 

 types^ are of necessity better made, as the paragraph in 

 cjuestion somewhat implies, but because, in general, an 

 •ichromatic condenser, even of the finest optical construc- 

 tion, does not focus within such narrow limits that a fine 

 adjustment motion is necessary. A well-made rackwork 

 will, in fact, give a sufficient degree of accuracy. 



.\s to the horseshoe foot, this has little to recommend it 



NO. 2204, VOL. 88] 



wlii-n lu»ii/i)i)iai, iiiuch i'->9 retain any d<.-fjrt-e o( »titbility 

 that po'iition. The method of damping down 5« u<uaQ 

 such that the instrument is under ■ ' 



finslon, and rert.iinly should any p 



will fffl thf cflTects of this to the i,;, ,„,,.. :i« 



that rlamping down is npcessary with the la: 's 



English make is not in accordanc*! with the ' lis 



recently had a microscope made by a leading Enjiiisli ma 

 which is even more stable in the horirontnl than the ver 



at any 



iOUS. 



...•• rM^nds is a poll 

 which some En^U 



position, and I should certainly ci 

 when using this instrument would 1 



The large body tube of the Contiir 

 distinctly in their favour, and one 

 makers have wisely thought fit to imitate 



As to the sensitiveness of the fine adjustment, thi« 

 perhaps a controversial point, the degree of sensitive! 

 required depending to a large extent on the user. .As 

 becomes more expert, it is realised that such extreme si 

 ness of movement is not required, but that it ii 

 for the movement to be absolutfly precise. Slownes* 

 the fine adjustment motion which is claimed as a ch.Tr.icte^ 

 istic of the Continental type has at least been equ 

 manv years bv an English maker. One w. 

 English fine adjustment moves the body tube 1 25.? 

 of an inch per division of the milled head, and th 

 practically the same as that provided in one of the n* 

 of Continental instruments. 



.As to the relative merits of ground-in as comj' 

 with sprung motions, there is no doubt, from the poii 

 view of the ordinarv microscope user, that the grour 

 fittings are preferable, but this does not of necessity :; 

 to those W'ho use their instruments with great care 

 who are quite capable of making the necessary ad; 

 which the sprung fittings provide. When once . 



in fitting has become loose from wear there is n<. 



do but to return it to the maker for replacement, wh' 

 with the sprung fittings, by careful use, they car 

 adjusted from time to time and the instrument kef 

 perfect working order. However, this point has been 

 or less settled in favour of the ground-in method, as 

 ing English makers are now providing (and some of ■ 

 have done so for several years) instruments in whir] 

 their fittings are ground. So far, the respective cl.iims of 

 the English and Continental stands are fairly well s. t out, 

 although much of the information given is to be found in 

 makers' catalogues ; but it is when we come to that part 

 of the article headed " English and Continental Micro- 

 scopes," and in which, therefore, we look for a careful 

 comparison of the merits and demerits of the two t>-pes, 

 that astonishing claims are made. While it is scarcely 

 possible to consider fully the question of the ei"olution of 

 the microscope, it must at once be said that the statements 

 made are not strictly in accordance with the real facts 



The modern Continental microscope, what< v- r its 

 advantages or disadvantages, has been evolved Inr^^ Iv as 

 the result of a consideration of the English model. Here 

 we are told that the present-day English microscope is a 

 degenerate form of what was originally a complicated and 

 massive piece of mechanism, the multiplicity of r.icks and 

 screws of which were a source of delight to dilettanti, while 

 the modern Continental instrument is an evolution from 

 an exceedingly simple, and by inference highly satisfactory 

 design. To put it plainly, this is not the fact ; the refine- 

 ments on a modern Continental stand have almost entirelj 

 been borrowed or copied from more perfect English models 

 We are told that the serious worker in science has not th< 

 time to play wjth the large variet\- of fittings in the English 

 stand, while the dilettante is content to manipulate these 

 with the result that he is both " physically and mentalh 

 exhausted." In any case, if the user of a microscop* 

 requires an instrument that will deal with a large numbo 

 of objects in a given time, it would be quite easy to devis* 

 some mechanical arrangement. Fortunately, there are sdl 



