196 PROCEEDINGS OF THE 



held together by a kind of cement, the difficulty of avoiding." 

 injury in an attempt at rubbing them down is very great, while-- 

 not a few cases occur where, though the shell is calcareous, it has. 

 embedded in its substance particles of sand of varying size and. 

 hardness. These examples were dealt with by Mr. Barnard's 

 process with a success which could be obtained by no other- 

 means, and numerous examples were thrown on the screen where, 

 the internal structure was admirably displayed, of course 

 without any chance of disturbance having taken place, as the 

 tests had not been interfered with mechanically in any way^ 

 In Astrorhiza arenaria the branching tubular body-cavity w^as^- 

 perfectly sho^vn in spite of the incrustation of sand on the ex- 

 terior. Cyclammina cancellata gave a view of the labyrinthine- 

 wall-structure which could not otherwise have been obtained,, 

 quite free from any suspicion of alteration, and absolutely 

 without injury to the original specimen. Orhiculina adunca^ 

 which is normally opaque, revealed its spirally wound coil of 

 chambers in the most perfect manner, notwithstanding the- 

 difficulty of the varying thickness of the shell in different parts^ 

 Fossil forms even, such as Nummulites, were successfully dealt 

 with, and a quite remarkable amount of structure was shown 

 as still existing capable of demonstration. 



Mr. J. E. Barnard said : 



" Some previous work on the application of X-rays to the-- 

 study of microscopic objects had been reported upon in the 

 Compter Rendus, but the methods adopted did not seem to pro- 

 mise very satisfactory results. As an outcome of the fine^ 

 work of Laue, Friedrich and Knipping the molecular structure 

 of crystals was exactly demonstrated, and it was shown also that 

 X-rays were a form of light differing only in wave-length from 

 the Herzian rays or those of other parts of the spectrum. This 

 work was followed up by Bragg in this country and it con- 

 stitutes one of the greatest advances in physical science that 

 has been made in recent years. The important fact that X-rays 

 could be reflected from a crystal surface was one of the results 

 arising from these experiments. 



" We are confronted with the fact that for the last thirty 

 years, with one exception, there has been little actual advance 

 in microscopic optics. We know, too, that theory and practice 

 are almost in agreement : that the optician has been able to* 



