Aug. 1, 1S70.] 



HARDWICKE'S SCIENCE-GOSSIP. 



377 



37th plates of which contain excellent figures of 

 Isoetes spores. Those represented on plate 37 as the 

 spores of Isoetes velata, are almost identical with 

 the " Hasan-i-Yusaf," and leave not the slightest 

 reason for doubt as to the source of the latter. 

 This will be seen by comparison of our rough 

 transcript of the spores of Isoetes velata, from the 

 " Flore d'Algerie," with the other figures above. 





Fig. l6r. Spores of Isoetes velata. 



It only remains to ascertain what species of Isoe- 

 tes is found on the lakes of Kashmir, and to com- 

 pare the spores with this substance. The form, 

 texture, porcellanic appearance, resistance to acid, 

 place, and mode of collection, affinity to Selaginella, 

 and agreement with Griffith's figures, all indicate 

 one source, which we have indicated, for the 

 " Hasan-i-Yusaf ; " and we commend this explana- 

 tion with some confidence, as removing the chief 

 difficulties- in the way of identification of this mys- 

 terious substance with its botanical source. 



SEPIOSTAIRE. 



rf^IIERE may be seen on many of our coasts, after 

 -■- a storm, amongst divers waifs and strays, a 

 small boat-shaped piece of exceedingly chalk-like 

 substance, commonly known as cuttle-bone, though 

 it has really little, if any, title to be styled bone. 

 This " bone " is in the animal inclosed in a little sac 

 within the body, and it is very readily disengaged 

 therefrom, if our friends chance to discover a defunct 

 cuttle. The powdered bone is, we believe, com- 

 monly to be met with in perfumers' shops, under a 

 multiplicity of names, being sold as tooth-powder, 

 &c. &c, to a considerable extent ; and school-boys 

 are usually aware of its ink-extracting qualities ; 

 which said powers of eiasement appear to have 

 somewhat puzzled some young students of science 

 at one of our educational establishments lately, if 

 their published memoirs be credited.] And, in truth, 

 it is to these very ink- erasing properties that I owe 

 my acquaintance with the cuttle-bone. A piece was 

 sent me by a microscopical friend with these notes, 

 " Can you make anything of this cuttle-bone ? — our 

 boys use it (on the sly, I believe, but I won't 

 * split ') to rub out their ink-blots." On its receipt 



I set to work to sectionize it very extensively, and 

 it has occurred to 'me that some of the readers of 

 Science-Gossip may be interested in a brief resume 

 of my work, and a few sketches from my slides. 



The Rev. J. G. Wood thus writes of the bone : — 

 " If it be cut across and examined through a lens, 

 the cause of the lightness will be perceived. The 

 plate is not solid, but is formed of a succession of 

 excessively thin laminae, or floors of chalk, each 

 connected with each by myriads of the tiniest 

 imaginable chalky pillars." This is a popular 

 description, but does not possess the merit of being 

 faithful to facts. Examined under a sufficient 

 power, the cuttle-bone certainly has not a chalky 

 appearance, the calcareous plates or floors, even, 

 assume a transparency which would certainly not 

 call up the idea of a section of chalk, and the 

 laminae, or "pillars," which support the floors are 

 really sinuous plates of remarkable tenuity and 

 wonderful delicacy. A very cursory view, however, 

 might lead one to regard these laminae as pillars — 

 not round, but conical, and arranged in a most 

 arbitrary manner ; and the full truthfulness of Dr. 

 Carpenter's description (" Microscope and its Reve- 

 lations ") is not seen until many very careful^sections 

 have been made. 



Fig. 163. Sepiostaire, vertical section. 



We give (fig. 168) a view of a vertical section across 

 axis, viewed as an opaque object. It will be seen 

 that there are evidences of a certain sinuosity in the 

 arrangement of the " pillars," which would awake 

 suspicion as to their true character. We notice 

 that each lamina is attached to the surface of the 

 floor by a thickened adhesion, and that it may easily 

 be separated therefrom. 



Eig. 169 gives a view of what one of my friends has 

 called a ground-plan of sepiostaire. It is simply a 

 " block" of " pillars," with the upper floor removed 

 very carefully, to enable us to see the true arrange- 

 ment of the laminae. A section of the kind, with 

 an oblique slice taken off it, shows the sinuosity 

 well. 



As transparent objects, sections of sepiostaire are 

 exceedingly beautiful when used with the polari- 

 scope. The section should be very thin, oarefully 



