1876.] Microscopy. 758 
September, 1871, being there estimated as “a little expedient of great 
practical convenience.” Ever since that time the present writer, among 
others, has used them habitually, shown them freely, and not unfrequently 
iven them away. ‘The mirror may be either of silvered glass or of pol- 
ished metal. In some cases the object-slide may lie directly upon it while 
it rests upon the stage; but frequently the object-slide is best elevated 
slightly above it.. The mirror is most conveniently made of the size of a 
slide (3x1) and furnished with glass strips at the ends to support the slide 
at any required height ; but it may be made smaller, say one inch square 
or round, and sunken in a brass or wooden stage-plate, or for stands hav- 
ing a sub-stage of any kind it may be made of suitable size and supported 
from the sub-stage and adjusted for height in the same manner as the 
achromatic condenser. It has the advantage of great ease of manipula- 
tion and applicability to any stand, and the drawback of being liable to 
be interfered with by the presence on the slide of such obstructions as 
paper covers or opaque cells or rings of varnish. Within a few months 
past it has been brought forward by Rev. John Bramhall, of Lynn, 
England; its previous use and publication having either escaped the 
notice or slipped from the memory of himself as well as of the distin- 
guished microscopist who has indorsed it and proposed to name it after 
him. 
Ture Ricumonp Fossil EARTH: -~ The recent excavation of a tun- 
nel by the Chesapeake and Ohio Railroad Company, through. that part 
of the city of Richmond, Va., known as Church Hill, has intersected this 
famous deposit for a distance of three fourths of a mile, and afforded 
rare facilities for study and the collection of material. C. L. Peticolas 
ttention to the work of obtaining 
describes the stratum 
above tide water. Before exposure to the air it is tough and = 
having the color and solidity of bituminous coal and requiring to bed 
removed from the tunnel by means of blasting ; but after exposure 
some time it crumbles to a fine powder of almost snowy — A 
sisting in general of about one half fine pure clay, one fourt gre = 
sand, and one fourth fossil diatoms interspersed with tbe h wa 
ules and a few Polycystina. The abundance and ye e e A 
forms vary greatly in different parts of the stratum, 
being the richer. : ; 
: sane monthly series of illus- 
Micro-PHotToGRAPHS IN HisToLoGy.- The “a ne Be cok 
; : istology, b 
trations of normal and petbologicsl A Aali an kai advanced suffi- 
i i i of tissues, 
