Boyal Microscopical Society. 211 



like the rack-boxes, it is a case of trouble in searching for an object. 

 It would be an improvement if each tray slid in on fillets, so that 

 one might be taken out without disturbiog the others, and by 

 deepening the face labels could be jDlaced outside. To do this would, 

 however, spoil the compactness^ and in part materially cripple their 

 intended utility. 



D. — Piper's original Portable Horizontal Slide Cabinet, as 

 described by himself,* is composed of any number of flat cardboard 

 trays, divided into six or more compartments, each holding a single 

 slide in a horizontal position. The trays are enclosed in a strong 

 millboard box, the front of which is made to fall down, so as to 

 permit the trays to be readily withdrawn. When closed, an elastic 

 band renders the whole firm and secure. 



" It may be made of any desired capacity. Specimens are placed 

 on the table capable of receiving from six to two hundred and fifty 

 slides. The smallest is well adapted to contain a ' half-dozen 

 series ' of anatomical or other subjects ; and its great strength, 

 combined with lightness, makes it peculiarly available for transmis- 

 sion through the post. 



" The one figured above (I. c.) is, however, that to which I would 

 more particularly call your attention, being of a convenient size, 

 and suitable for carrying in the pocket. It contains six trays, and 

 will therefore hold three dozen shdes. 



" Among the advantages which may be derived from the 

 cabinets, I will mention the convenience of displaying, at one view, 

 the entire collection of slides, and the facility thus afibrded for the 

 selection of any required specimen, without the troublesome search 

 and difiiculty of removal frequently experienced with the old form 

 of box, in which the slides are dropped (out of sight) into perpen- 

 dicular grooves. It also prevents the possibility of the covers 

 becoming detached by shaking about in transit, which is important 

 when it is to convey a rare or valuable collection. 



" The trays, being all of uniform size, may be transferred from 

 one cabinet to another of larger or smaller dimensions, without 

 necessitating the disturbance of the slides. In addition to its 

 portability, it possesses the merit of cheapness, dm'ability, and neatness 

 of appearance." 



The advantage of Piper's horizontal cases is marred by the 

 trays resting on each other, and hence is only applicable to a very 

 limited series of objects. The Eulensteinf collection of the British 

 Museum, containing one hundred types of diatoms, is contained in 

 a case after Piper's pattern, but larger, and for this purpose it 

 answers very well. 



* ' Trans. Micros. Soc. and Journ.,' 1867, vol. xv., 2nd Ser., p. \Q. 

 t ' Diatomacerum Species TypiciB, Studiis,' Th. Eulensteiu. Cent I. Stutt- 

 gartiffi, 1867. 



