^oumlu.Tprlfi?rJ7a] PROCEEDINGS OF SOCIETIES. 213 



spoken of. He had to cany on some experiments at a railway station, 

 where everything was in a state of vibration (so much so that when 

 heavy trains passed small scali)els chattered on an earthen plate) ; 

 and he found that the Eoss model with a i objective worked admir- 

 ably. He did not assert that the Eoss model was the best in all 

 respects ; but at the same time he could not see any logical inference 

 that the tremor was due to motion in the eye-piece ; and while the 

 point of support was near the object-glass, this has but little motion. 



Dr. Carpenter. — Let any gentleman take the eye-piece between 

 his fingers and give it a touch, he will at once convince himself that 

 the tremor is from the eye-piece. You may touch the other portions 

 of the instrument and produce no tremor. 



Mr. Lobb said, without reference to any particular make of micro- 

 scope, he would suggest that, having had considerable experience in 

 the use of high powers, unless the slow motion be excessively steady, 

 there must be a great vibration of the object under inspection. To 

 view the objects satisfactorily, not only must the instrument be steady, 

 but the slow motion also. 



Mr. Ladd thought that it was scarcely fail" to take two single 

 microscopes and compare them in the manner alluded to. He could 

 understand that if a microscope were taken which was a little worn, 

 the screw that tightens the bar and would make it steady might be in 

 fault. It was quite possible, in selecting a microscojje at random, 

 to account for all the shaking sjioken of by Dr. Carpenter, since all 

 depends upon the way in which the instrument is screwed wp. There 

 is the round bar at the bottom, and a little shake at that part would 

 account for all Dr. Carpenter had referred to. 



Dr. Carpenter explained that the instrument used by him was not 

 worn at all ; it was one recommended in the Canadian survey. 



The President proposed a vote of thanks to Dr. Carpenter for his 

 papers. 



Dr. Carpenter said he ought to apologize for the mistake he had 

 made in his book. He had overlooked the fact that the particular plan 

 was Mr. Jackson's ; but he thought the title of his paper should re- 

 main, and he would add an explanatory note. 



Mr. Slack said that he was sure the Society was much obliged to 

 Dr. Carpenter for the interesting subjects he had brought before them, 

 and that general regret would be felt that there was not sufficient 

 time to discuss them properly. 



The President then announced that the soiree would be held on 

 the 20th April next, when he hoped a larger number of Fellows would 

 bring their microscopes than had done so on two or three previous 

 occasions. 



Mr. Beck inquired whether the soiree was to be of the same 

 character as formerly. Without wishing to say anything against the 

 plans which had already obtained, he should very much like to see a 

 new mode of conducting this annual entertainment. It was highly 

 desirable, he thought, that there should be one day in the year on 

 which the Fellows could meet for some useful purpose, and when they 

 can see the scientific exhibition of microscopes and microscopic objects. 



