107 



" Paper on a New Marine Alga " The Author. 



" Annals of IS'atiiral History " ... ... Purchased. 



Mr. Morland exhibited one of Brown and Sharpe's American 

 wire gauges, which he thought would be found very useful as 

 affording an easy means of ascertaining the thickness of cover 

 glasses. Measurements could quickly and easily be made 

 down to the j-g-^Q-th of an inch. The gauge was handed round 

 for inspection. 



Mr. R. T. Lewis said as this subject had been brought for- 

 ward he might again mention Trotter's patent gauge as being 

 also available for the same purpose. This was made of steel, 

 and being only two inches long was easily carried in the waist- 

 coat pocket. Its construction was very ingenious, and by 

 means of two sliding scales on the Yernier principle it showed 

 six measurements at the same time, i.e., the English standard 

 wire gauge with its equivalents in decimals of an inch and of a 

 millimetre were shown on one face, and on the other, for the use 

 of electricians and others, the sectional area of the round wire 

 in fractional parts of a square inch, the weight of copper wire 

 per 100 feet, and the quantity of current it would theoretically 

 carry. It required something of an education to be able to use 

 it with facility, but, like most other things, when you knew 

 how to use it the process was simple. 



Mr. J. E. Ingpen said the only difficulty he saw as to the use 

 of these gauges was that there was likely to be a difference in 

 the results according to the amount of pressure applied. This 

 he could not help thinking was a point rather against all 

 micrometer gauges which worked by touch, because in the 

 measurement of cover glasses it was specially necessary to be 

 very exact. 



The President said they would all recognize the desirability 

 of being able to ascertain the thickness of cover glasses, and 

 would therefore welcome any plan which would facilitate it. 

 They were much indebted to Mr. Morland for bringing this 

 little instrument before them. 



The President then read his Annual Address, postponed from 

 the last meeting for the reason then named. 



Mr. A. D. Michael thought that after the way in which it 

 had been received it was scarcely necessary for him to ask for 

 an expression of their thanks for the highly instructive address 

 to which they had just listened, not the least valuable part of 



