174 Transactions of the Society. 



stage "with its proper accessories, and the buU's-eye, mirror, and 

 illumination to match, are almost invariable accompaniments of the 

 low power. The observer can work hour after hour and with but 

 little fatigue. The object can be drawn with or without the 

 camera lucida ; and if it is a rock specimen the polariscope can be 

 used with ease. 



It was quite another matter in days gone by, when, however, 

 most lasting — indeed everlasting — work was done with the aid of 

 the low and imperfect powers. Compare the luxurious microscopist 

 of to-day with the painfully labouring yet ever illustrious Swam- 

 merdam. In working at his memoir on the Day-fly, the figures 

 in which are marvels of exactitude, Swammerdam excited the 

 admiration and pity of Boerhaave, who wrote of him as follows : 

 " All day he was employed in examining objects, and at night 

 described and delineated what he had seen by day. At six in the 

 morning in summer, he began to receive sufficient light from 

 the sun to enable him to trace the objects of his examination. He 

 continued dissecting until 12 o'clock, with his hat removed, lest it 

 should impede the light, and in the full glow of the sun, the heat 

 of which caused his head to be constantly covered with profuse 

 perspiration. His eyes being constantly exposed to a strong light, 

 the efiect of which was increased by the Microscope, they were so 

 affected by it that after midday he could no longer trace the 

 minute bodies which he examined, although he had then as bright 

 a light as in the forenoon." 



But it was long after the time of Swammerdam before comfort 

 and microscopical investigation were associated. Even after the 

 achromatic system had been discovered and utilized, the " doublet " 

 and " triplet " were used ; but these scientific atrocities gave way 

 to the combination of lenses now employed, and the days of com- 

 paratively easy working began. Great care was taken in the manu- 

 facture of the objectives of low power in this country, and magnifi- 

 cent specimens of science and art were speedily brought forth. 

 I speak under correction, but it appears to me that there has not 

 been any great improvement upon the low-power objectives which 

 were produced by our great Microscope-makers a quarter of a cen- 

 tury since. There has been an influx of second-rate low-power 

 objectives, together with those of a high class, and the reason has 

 been, not from any deterioration in the skill of the artizan, but 

 from the belief, on the part of the public, that low-power objectives 

 are more easily made than those of high power, and that therefore 

 they should not be so costly. This is a great mistake, and the 

 mischief produced by it, in the demand for cheap low-powers, has 

 not been checked by the experience of those microscopists who 

 almost entirely use objectives of a high amplification. Many 

 investigators rarely employ a low power, and provided their high 



