Aug. 3, 1888.] 



SCIENTIFIC NEWS. 



105 



IMPROVED LABORATORY OVEN AND 

 BATH. 



'T'HE accompanying illustration represents Professor 

 Reynolds' improved water oven and bath for 

 laboratory use. It is a well-contrived and most useful 

 apparatus, and we have much pleasure in recommending 

 it to chemists and physiologists. The illustration shows 

 an enclosed chamber on one side, with a glass door, and 

 there is a similar chamber on the opposite side, with a 

 space between the backs of the two chambers. There is 

 also an enclosed space about 3 ins. deep under the two 

 chambers, which is filled with water. The water is 

 supplied through the upper tube at the end, and it is 

 kept at a constant level by an overflow pipe inserted in 

 the short vertical tube shown in the figure. If there be 

 any waste water it is carried away by the bottom tube 

 at the end. At the opposite end (not shown in the 

 figure) there is a water gauge, by means of which the 

 water level can be seen at any time. The water is 

 heated by a Bunsen lamp underneath, and the whole of 

 the apparatus is made of copper which conducts heat 

 readily without much loss from radiation. Any tempera- 



Reynolds' Improved Oven and Bath. 



ture up to 100 degs. C. (212 degs. F.) can be steadily 

 maintained, and this cannot be said of the water baths 

 generally in use. Each of the enclosed chambers is 

 fitted with shelves to receive test tubes, etc., and in each 

 there is provision for a thermometer. On the top of the 

 casing there are three or four openings fitted with covers 

 to receive evaporating dishes, and at one end is a curved 

 tube, through which the steam or water vapour escapes. 

 This tube can be connected with a condenser, and then 

 distilled water can be obtained. The apparatus has been 

 neatly made by Messrs. Becker and Co., of 34, Maiden 

 Lane, W.C., and it has evidently been designed by one 

 who not only has a practical acquaintance with what is 

 required, but who also has a knowledge of the scientific 

 principles on which its success depends. 



SIMPLE EXPERIMENTS IN PHYSICS. 



"TPO all matter must be attributed two essential qualities ; 

 - 1 first, that in virtue of which it occupies space, and 

 which is known as extension ; and second, that which 

 allows only one particle or atom of matter to occupy a 

 given space — the property known as impenetrability. 

 That matter occupies space is appreciated by our senses, 

 and needs no particular proof, but that two portions of 

 matter cannot occupy the same space at the same time 

 sometimes seems anomalous, as is shown by some of 

 the following experiments. Into a tumble/ filled with 

 alcohol may be crowded a hatful of loose cotton without 



causing the alcohol to overflow. The success of the ex- 

 periment depends the slow introduction of the cotton, 

 allowing the alcohol to invest the fibres by capillarity 



Fig. 1. 



-A Hatful of Cotton 

 Alcohol. 



in a Tumblerful of 



before they are fairly plunged beneath the surface of the 

 alcohol. In this experiment the penetration of alcohol is 

 only apparent ; the fibres displace some of the alcohol, 

 but the quantity is so small as not to be observable. If 

 the cotton were compressed to the smallest possible 

 volume it would be found to occupy but very little space. 

 So small a body would be incapable of raising the level 

 of the alcohol enough to be appreciable by an ordinary 

 observer. A more puzzling experiment consists in 

 slowly introducing some fine sugar into a tumblerful of 

 warm water. A considerable quantity of sugar may be 

 dissolved in the water without increasing its bulk. 



Fig. 2. — Solution of Sugar in Water. 



Here the physicist is forced to acknowledge that either 

 the water is penetrated or its atoms are so disposed as 

 to receive the sugar between them, possibly in the same 

 way as a scuttle filled with coals might contain also a 



