CORKESPONDENCE. 289 



solved into beads, but ai^parently not so compressed as those of 

 Cymhclla Ehrenhergii. 



In all the above observations the adjusting collar of the glass 

 remained unaltered, just midway between " covered" and " uncovered." 

 May I add that this objective contains in itself an adaptation for 

 immersion use, and while it performs so well on lined objects, it gives 

 a superb figure of Lepidocijrtus curvicollis. 



I am, Sir, your faithful servant, 



E. Corbet Singleton. 



On Mr, Singleton's Observations. 



To the Editor of the ' Monthly Mi'croscojncal Journal.^ 



Denstone, November 9, 1874. 



Sir,— While I am much obliged to the Eev. E. Singleton for his 

 readiness to ventilate the question of straight candle-light illumina- 

 tion, I must confess I am disaj)pointed at the general tone of his 

 letter, and the covert vein of sarcasm which runs through it. This 

 has been the more surprising to me, as I am conscious of having 

 taken unusual pains to avoid giving offence, and to write nothing that 

 might rouse up any of the genus irritabile microscopicormn. 



Indeed, it would be well for all of us, when we have to remark 

 upon the jierformanccs of another, of which we have before us only a 

 brief printed account, to exercise a certain amount of caution, lest, 

 while criticising, we ourselves fall into mistakes. With nothing but 

 an abstract to guide us, and in the absence of the writer himself, we 

 are not always certain what is the strength of the point we would 

 attack ; nor do we know but that our opponent may have an awkward 

 trick of keeping back his strongest troops in the reserve. 



Mr. Singleton must himself by this time regret the peculiar turn 

 he gave to his last sentence. 



" If he means that it has detected the longitudinal lines of that 

 diatom, it would be a real boon to microscopists to tell them of the 

 feat." 



Indifferent persons who take up his letter will read between the 

 lines something of this sort : — 



" S. gemma is a test * of prodigious difiiculty. Mr. Hickie seems 

 to hint that he has resolved it with a 7} inch. Either he has so 

 resolved it, or he has not ; he declines to say which. I will force 



* The Germans, in spite of the Grundlichkeit we are in the habit of ascribing 

 to them, are in these matters pretty much as we are ourselves, and quite as much 

 given to copying one from another. See Dr. Hager's 'Das Mikroskop,' p. 36. 

 An exception may be made in favour of Dr. E. Hartnack, of Potsdam, as his 

 blunders are usually original. But the Herrschaft zu Waisenstrasse, though great 

 opticians, are by no means great manipulators, as I know by experience. Some- 

 thing of the same kind appeared also in an early number of this Journal ; but the 

 writer has since, in my hearing, candidly retracted his error. To those who have 

 no opportxmity of judging otherwise, I would recommend a glance at Dr. Wood- 

 ward's photograph of this diatom. 



