68 
lating fan driven by a a motor is capable of renewing the 
entire body of air in the room in a few minutes and thus prevent- 
ing the escape of noxious gases into the contiguous laboratories. 
e second corner of the wing is occupied by the photo- 
graphic laboratory and balance room, which is equipped with an 
outfit comprising a set of screens, cameras, and a selection of 
anastigmatic and planar lenses which provide for almost every 
contingency of indoor and outdoor work, including photomico- 
raj The adjoining dark room opens directly into the hallway 
and contains the apparatus necessary for developing and printing. 
The basement floor of the museum contains two rooms d 
voted to laboratory purposes. One is planned for he storage of 
chemicals and other supplies, for glassblowing and general prep- 
aration work. The second is a constant temperature room, 34 
by 20 feet furnished with double walls, doors and windows ; 
this is designed to be separated into several ie chambers in 
which different temperatures may be maintained. A series of 
thermographic tests of the temperature resulting from outside 
and inside causes are now in progress, from which the final fit- 
tings necessary for absolute control of the different temperatures 
may be determined 
e least important part of the organization of 
the laboratories consists in the opportunities for culture and ex- 
perimental work offered by the plantations and_ horticultural 
houses of the Garden. The space at the disposal of an intend- 
ing investigator will be found most ample for all contingencies 
ich can be foreseen at the present time. 
. T, MacDoueat. 
A COLLECTION OF OLD MICROSCOPES. 
A collection of old pean: brought together by Mr. 
Charles F, Cox, of the Board of Managers, has been given by 
him to the Garden and ere rm a special laboratory exhibit. 
The principal historical and structural details of the instruments 
are given below 
o. 1, Part ar rude wooden microscope on circular porcelain 
base, with one objective. Origin and date unknown. 
No. 2. Microscope with wood and eee tube supported 
