82 
No. 45 is a penholder used by Dalton. No. 46, leaden 
grain weights made by Dalton from sheet lead, and stamped 
in numbers by him ; No. 47, iron punches used by Dalton 
for this purpose. No. 48, a glass lens, wrapped in a piece 
of paper labelled, in Dalton’s writing, “Sun’s focus 42 
inches.” No. 49 is a paper containing “10th of grains,” 
made by Dr. Dalton of iron wire. The paper in which these 
are wrapped is part of a note from one of Dr. Dalton’s 
pupils (as is well known he lived by teaching mathematics 
at half-a-crown per lesson), in which the writer presents his 
“compliments to Mr. Dalton, and is sorry that he will not 
be able to wait upon him to-day, as he is going to Liver- 
pool with a few friends who are trying the Railway for the 
first time. Mr. D. may fully expect him on Monday at the 
usual time.” No. 50 are bottles of tin, earthenware, and 
silver, some of them being common penny pot ink bottles. 
Each has a thermometer tube cemented into the neck of 
the bottle, and these tubes are provided with paper scales. 
These were used by Dalton probably for experiments on 
radiant heat. No. 51 is a manometer tube used by Dalton; 
it consists of a tin vessel attached on either side to leaden 
tubing, and having a thermometer-tube closed at the upper 
end, and provided with a divided scale, fixed into the upper 
portion of the tin vessel. No. 52, Dalton’s balance, made 
by Accum, and capable of arrangement as hydrostatic bal- 
ance, with weights and counterpoises. 
The following letter from Mr. Arthur Wm. Waters, 
dated Naples, February 9th, 1876, was read by Mr. Baxen- 
DELL : — 
Having expected to return ere this, I thought that, in the 
conversational hour before papers are read, I should have 
been able to say a few words on the Aquarium at Naples, 
where I have been working for six weeks, the British 
Association Committee for the establishment of zoological 
