228 



HARDWICKE'S SCIENCE-GOSSIP. 



before the descent of hail. This cannot be a common 

 phenomenon, or it would have been more generally 

 remarked. 



12. Structure and size of the hailstones. — Observa- 

 tions of the structure of hailstones are seldom of any 

 use, as the necessary precautions are generally 

 neglected in conducting the examination. The ice 

 of which they are composed undergoes a rapid 

 change when exposed to a high temperature, so 

 they ought to be collected immediately on descent. 

 Further, as collision with the ground is liable to 

 cause alteration of shape, if not entire fracture, it is 

 well to catch the hailstones destined for examination 

 upon a piece of flannel, which not only preserves the 

 stones in their entirety, but, being a bad conductor 

 of heat, keeps them from dissolving rapidly. The 

 scrutiny may then be conducted in a cool room. 

 Size should be determined by accurate measurements. 

 Such vague terms as the " size of peas," or the " size 

 of eggs," or "like large nuts," are useless for 

 scientific purposes. 



The above points may be supplemented by any 

 others that the experience of observers may suggest 

 or that peculiarities in individual storms may require. 

 J. A. Westwood Oliver. 



Athencsum, Glasgow. 



RECREATIONS IN FOSSIL BOTANY. 



Calamites. 



No. VI. 

 By James Spe-nxer. 



EVERY student of geology is familiar with the 

 sandstone and ironstone fossils called cala- 

 mites. They derive their name from calamus, a 



Fig. 134.— Transverse Section of Fruit of Calamite. 



"reed," on account of their outward resemblance to 

 the reed plants, such as canes and horsetails. 



But it is now well known that these sandstone 



and ironstone fossils do not represent the real forms 

 of the plants when growing erect in their native 

 habitat, but are merely the casts of the interior of the 

 original plants, which were plain and smooth 

 externally and not ribbed and jointed. 



In our Halifax coal balls we meet with calamites 

 in a perfect state of preservation, and of various sizes, 

 the best preserved specimens being generally small 

 in size, though fragments of larger ones are some- 

 times met with. A transverse section of a calamite 

 shows that the centre was hollow, except at the nodes, 

 and that the woody cylinder was composed of a 

 number of vascular wedge-shaped bundles of vessels 

 which were arranged in regular radiating laminoci 



Fig. 135. — Vertical Section of Fruit of Calamite, 

 [n, protective bracts ; /', peltate scales.) 



Each of these wedges terminated at the inner side 

 in a rounded point which was perforated with a hole 

 or canal that extended along each wedge from node 

 to node. This canal is one of the distinguishing 

 features of the calamite. At each node the vessels 

 forming the woody wedges formed a series of arches 

 in such a way that while one portion went to help to 

 form the wedge on the right, the other portion helped 

 to form that on the left. These wedges were gener- 

 ally joined together at their peripheral bases or out- 

 side of the woody zone, while the space between 

 each wedge at the inner side was filled with the 

 cellular tissues of the pith, which also formed a thin 

 wall around them, leaving the centre of the plant 

 hollow, except at the nodes where a tliin layer ex- 



