1892.] MICEOSCOPrOAL JOURNAL. 135 



The Janssens must have cxpcrinientecl upon a variety of forms, 

 as was most natural under tlie circumstances. Their instruments 

 have commonly been described as tubes of gilded copper, one 

 inch in diameter and six feet long, being, probably, telescopes 

 converted into compound microscopes, supported by dolphin- 

 shaped pillars over an ebony base, on which rested the object to 

 be examined. One of these is said to lia\e been carried to 

 England about the year 1^90, and to have been shown to William 

 Borrell and others. Very diflerent and far more crude is the 

 '■• microscope authoitiqiic dc Ja?issc}i'" contributed to the expo- 

 sition by the Zealand Society of Sciences. This consists of rough 

 tin tubes, soldered, about two inches in diameter and, when com- 

 bined as a microscope, some i 2 to 14 inches long, containing an 

 ocular and objective, each consisting of a single lens of about three 

 inches focus. It has no stand, but is held in the hands and aimed, 

 telescope-fashion, at the object, which it magnifies from o to some 

 ^ or 6 diameters, according to ihe extension of the tubes. Though 

 very rudimental, roughly fitted, and to our ideas absurdly inef- 

 ficient, it is still evidently a microscope, and none the less so if 

 it was originally an experiment in t#lescope-making. Therefore, 

 conceding its genuineness, which, though attacked in the interests 

 of other claimants, does not seem yet to have been successfully 

 controverted, and that its maker was aware of the possibility and 

 effect of focusing it upon near objects, which is so probable as to 

 be practically certain, this instrument takes rank as the earliest 

 compound microscope yet known ; it carries the invention back 

 from the 17th to the i6th century, from Italy to the Netherlands, 

 from Galileo (already rich in honors) to Janssen, and it vindi- 

 cates our exposition as a tricentennial. 



A cut of Janssen's Microscope may be seen in the " Cantor 

 Lectures on the Microscope," p. ']. 



The remainder of the historical exhibit presented an interesting 

 variety of the curious and often fantastic constructions of the ryth, 

 iSth and early part of the 19th century. Their optical parts were 

 so primitive and inefficient as to impress one, at the present day, 

 with great respect for the intelligence and perseverance of any- 

 body who succeeded in doing any useful work with them. Their 

 stands were clumsy and often grotesque, many having wooden 

 bases and huge bodies of wood or pasteboard covered with paper 

 or leather, and often highly decorated with chasing or paint or 

 gilt, the whole appearance being suggestive of the cabinet-mak- 

 er's and bookbinder's rather than of the optician's art ; and the 

 brass-work, what there was of it, followed the fashion of the cen- 

 turies, running into scrolls and dolphin or dragon forms and in- 

 genious elaborate devices instead of the severe practical utility of 

 the present day. Many of the instruments were focused by screw- 

 ing the whole body down with a very coarse movement, through 

 the collar which supported it, toward the stage ; a method re- 

 vived in fine brass-work in the clinical microscope of Tolles a few 



