300 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1925 



writin:,'. as l.oinK desirous the gentlemen of the sooioty should without trouble 

 1k' enabled to examine many of those objec-ts on which he had made the most 

 considerable discoveries. 



Several of these objects yet remain before the microscopes, tho' the greater 

 number are broken off, which was proliably done by the shakinj? of the boxes 

 in the carriage. I have nevertheless added a translation of the register, as it 

 may serve to give a juster idea of what Mr. Lcuwenhoek design's by this 

 legacy; and also be of use, by putting any curiims ob.server in mind of a 

 number of minute subjects that may in a particular manner deserve his 

 attention. 



Then follows a list of the objects, which maj' conveniently be 

 omitted. 



For the construction of the.se instruments it is the .same in them all, and 

 the apparatus is very siniide and convenient: they are all single microscopes 

 consisting each of a very small double convex glass let into a socket between 

 two silver plates rivetted together and pierc'd with a small hole ; the object 

 is placed on a silver point or needle, which by means of screws of the same 

 metal provided for that purpose, may be turn'd about, rais'd, or depress'd, and 

 brought nearer or put farther from the glass as the eye of the observer, the 

 nature of the object, and the convenient examination of its .several parts may 

 require. 



Mr. Leeuwenhoek lix'd his objects if they were solid to this silver point 

 with glew ; and when they were fluid or of such a nature as not to be com- 

 modiously view'd unless spread upon glass, he first fitted them on a little 

 plate of talk, or excessively thin blown glass, which he aftenvards glewed to the 

 needle in the same manner as his other objects. 



The ob.servatinn indeed of the circulation of the blood, and some others, 

 require a somewhat different apparatus, and such a one he had, to which he 

 occasionally fix'd the same microscopes; but as it makes no part of this cabinet, 

 I shall omit giving any farther account of it. only taking notice that it may 

 be seen in a letter to the Royal Society of the 12th of January, 1GS9, and 

 printed in his Arcana naturae Detecta, No. G9. But I was willing to mention 

 just so much as it may serve to shew the universal u.se of these microscopes, 

 and as it induces me, among other things, to believe, these were the kind 

 of microscoites generally, if not solely, us'd by this curious gentleman in all 

 his observations, and to which we are oblig'd for bis most surprizing discov- 

 eries. 



Another particular to the same purpose, I would not omii, and that is, that 

 upon the late (pieen Mary's doing Mr. Leeuwenhoek the honour of a visit at 

 Delft, and viewing his curiosities with great satisfaction, he presented her 

 with a couple of his microscopes, which as I have been inform'd by one who 

 had them a considerable time in his hands were of the same sort as these, 

 and did not any ways differ from one of the 13 cases contain'd in the drawers 

 of this cabinet. 



The glasses are all exceedingly clear, and shew the object very bright and 

 distinct, which nnist be owing to the great care this gentleman took In the 

 choice of his glass, his exactness in giving it the true figure; and afterwards 

 amongst nnmy, reserving such only for his u.se, as he upon tryal found to be 

 most excellent. Their powers of magnifying are different, as different sorts 

 of objects may require ; and, as on the one hand, being all ground glasses, 

 none of them are so small, and consetiuently magnify to so great a degree, as 

 some of those drops frfiiuciitly us'd in other microscopes; yet on the other, the 



