HARD VVICKE'S SCIENCE-GOSSIP. 



that various parts bear to each other. Suppose, for 

 example, he possess a properly-prepared slide of the 

 gizzard of the cricket or the spinnerets of a spider, 

 it would be a matter of little difficulty to dissect a 

 cricket or spider, and see how those organs are con- 

 nected with other portions of the insect. 



All of us who have exhibited our slides and instru- 

 ments at what are called scientific soirees have been 

 struck with the want of interest shown by the public 

 in the objects exhibited, and by the singular com- 

 parisons made use of. I have heard a section of an 

 injected tongue of a cat compared to a map of 

 England, and a valve of Heliopelta Metii shown with 

 black ground illumination, to the top of a thimble. 

 This want of appreciation may be easily understood 

 when we consider how small a portion of an object 

 even with a low power is seen (about i of an inch), 

 and, as is often the case, the exhibitor, who has pro- 

 bably purchased the object, can give no information 

 as to what is seen in the instrument. 



The inventor of the microscope will probably never 

 be discovered, and perhaps no one could ever claim 

 that merit. The magnifying property of spheroidal 

 transparent substances was no doubt discovered 

 and utilized many thousands of years ago, and it 

 has been stated that a convex lens was found in the 

 ruins of Nineveh. It is, however, only in recent 

 times that we have any authentic records of the 

 microscope. Dr. Brewster, in his "Treatise on 

 Microscopes," mentions that " Zacharias Jansen 

 presented one to Prince Maurice, which in 1617 came 

 into the possession of Cornelius Drebbel, of Alk- 

 maar, who then resided in London as mathema- 

 tician to James I., in which place he made micro- 

 scopes, and passed them off as his own invention. 

 These instruments were said to be 6 ft. in length, 

 and consisted of a tube of gilt copper 1 in. iu dia- 

 meter, supported by thin brass pillars in the shape 

 of dolphins on a base of ebony, which was adapted 

 to hold the object to be examined. Nothing, how- 

 ever, is known of their internal construction ; they 

 were probably nothing more than telescopes con- 

 verted into compound microscopes." Viviani, the 

 author of a Life of Galileo, says that this great man was 

 led to the discovery of the microscope from that of 

 the telescope, and that in 1612 he sent one to Sigis- 

 mund, king of Poland. The invention of the com- 

 pound microscope is, however, usually attributed 

 to Zacharias Jansen, or Zansz, spectacle-maker, of 

 Middelburg, in Holland, about the year 1590. 



About the middle of the seventeenth century we 

 come to a period when the learned men of the time 

 turned their attention to the construction and im- 

 provement of the microscope, and the early volumes 

 of the "Transactions of the Royal Society" fre- 

 quently contain papers on the instrument and the 

 discoveries made therewith. 

 In 1673 the great Lceuwenhoek contributes his 



first papers to the " Philosophical Transactions " 

 but before giving a short resume of his labours it 

 may perhaps be desirable to form some idea of the 

 kind of instrument he used. Henry Baker, P.R.S., 

 in his work on the " Microscope," edit. 1753, gives 

 figures and a description of one of Leeuwenhoek's 

 microscopes. At page 434 he says: — "Though 

 Mr. Leeuwenhoek's Microscopes are much talked of 

 very few People are acquainted with their Structure 

 and Apparatus, no Figure of them that I remember 

 having ever been made publick : 'tis therefore hoped 

 the Curious will be pleased to see a Drawing of them 

 taken with great Exactness from those in the Repo- 

 sitory of the Royal Society, which are all alike in 

 Form and differ very little in Size from this Drawing 

 or from one another." * 



Fig. 1. 



Fig. 2. 



Representations of one of Leeuwenhoek's Microscopes, 

 from " Baker on the Microscope." 



" The flat Part, a, fig. 1, is composed of two thin 

 Silver Plates, fastened together by little Rivets, b, 

 b, b, b, b, b. Between these Plates a very small 

 double convex Glass is let into a Socket, and a 

 Hole is drilled in each Plate for the Eye to look 

 through at c. A Limb of Silver, d, is fastened to 

 the Plate on this side by a screw, e, which goes 

 through them both. Another Part of this Limb, 

 joined to it at right Angles, passes under the 

 Plates, and comes out on the other side at /, fig. 2 ; 

 through this runs directly upwards a long, fine- 

 threaded screw, g, which turns in and raises or 

 lowers the Stage, h, whereon a coarse, rugged Pin, i, 

 for the Object to be fastened to, is turned about 

 by a little Handle, k; and this Stage, with the Piu 

 upon it, is removed farther from the magnifying 



* Leeuwenhoek bequeathed to the Royal Society a small 

 cabinet containing twenty-six microscopes and objects, of 

 which a description was given by Martin Folkes, Esq., in 

 No. 3S0 of the " Philosophical Transactions.'' 



