JUNE 27, 1884.] 
matter of the heating had been put into the hands 
of Mr. F. Tudor. The main coil heats the air to 50° 
or 60° C., and a supplementary coil at the foot of each 
flue heats it as much higher as required. As the 
steam main is below the boiler level, and the return 
below the tank for condensed water, the arrange- 
ment of these coils was quite difficult. Mr. Tudor’s 
fractional valve is applied to each coil, and so adjusted 
as to just fill the coil with steam; only the condensed 
water escaping at the lower end, and draining into a 
tank, from which it is raised by a Davidson pump. 
The boilers and engines are all in another building, 
some hundred and fifty feet away. The Davidson 
pump serves as a water-meter to register the quantity 
of water condensed in the coils. For this purpose a 
cylinder around which a piece of paper is wound is 
revolved by clock-work, and a pencil so connected 
with the pump piston that it is gradually moved in 
the direction of the axis of the cylinder by the action 
of the pump. The length of stroke and size of 
cylinder being known, an automatic record is thus 
obtained, showing the quantity of water condensed. 
It also affords a means of studying many other points, 
as it shows the time of letting on steam and shutting 
it off, of starting and stopping the fan, of opening 
the windows, etc. From the quantity of water con- 
densed, the amount of coal which should be con- 
sumed in heating and ventilating the building may 
be calculated. With the aid of this automatic ap- 
paratus, Mr. Woodbridge had studied the matter of 
cost, and had discovered a considerable waste, though 
he had not yet been able to arrive at its cause. The 
results of the system are fully as satisfactory as were 
anticipated. Professor Nichols has studied the chemi- 
cal composition of the air, and has found in the case 
of one room, after it had been fully occupied for one 
hour by eighty or ninety students, the following pro- 
portions of carbonic acid expressed in parts in 10,000, 
— Feb. 9, 4.3; March 5, 6.1; March 11, 4.5, — thus 
showing practically no contamination. In regard to 
moisture, Mr. Woodbridge thought a relative humi- 
dity of 40% at a temperature of 65° was sufficient, as 
with a low relative humidity it is much easier to keep 
the airsweet. Asa whole, the work is highly satisfac- 
tory, not because perfect, but because in so many 
respects it meets the wants it undertook to satisfy. 
New-York microscopical society. 
May 2. — Mr. Charles H. Denison, in a paper on the 
gold sands of California, said that the coast of Cali- 
fornia from its northern to its southern boundary, for 
a length of nearly seven hundred miles, is strewn with 
magnetic iron sand, or comminuted magnetite, carry- 
ing gold and some other metals. He described the 
discovery of gold in these sands at Gold Bluff, where 
the indications are, that the spot was once the mouth 
of an immense river, now extinct. The process of 
mining for gold among these sands was described; but 
this process, said Mr. Denison, has not proved profita- 
ble. Onthe Klamath River the gold is associated with 
the same sand, and with platinum and iridosmene; 
while, on the great San Joaquin River, zircons and 
stream cinnabar are its additional associates. He 
SCIENCE. 197 
mentioned, that, while the black sand is water-worn, 
the quartz is sharp and splintery, as if never subjected 
to the action of water. Nevertheless, beneath Table 
Mountain, where it was satisfactorily proved that it 
had been deposited by water, the gravel had the same 
sharp features. 
NOTES AND NEWS. 
In order to allow an interchange of courtesies 
between the British and American associations, and 
enable the members of the two associations to attend 
both meetings, the meeting of the American associ- 
ation for the advancement of science, this year, will 
take place at a later date than usual. 
The council of the British association has invited 
the fellows of the American association to join in the 
meeting at Montreal on the footing of honorary mem- 
bers; and the American association and the local 
committee of Philadelphia have invited the members 
of the British association, with their near relatives 
who may be with them, to take part in the Philadel- 
phia meeting. Invitations have been sent to the 
leading scientific societies abroad, inviting them to 
send delegates to the Philadelphia meeting. The 
probabilities, therefore, are, that the Philadelphia 
meeting will be largely international in its character; 
and it is likely that steps will be taken to form an 
international scientific association. At the same 
time with the association meeting, the International 
electrical exhibition will be taking place in Philadel- 
phia, and probably at the close of the week an elec- 
trical congress will be held. Other bodies will also 
be in session during the week, among them the Penn- 
sylvania state agricultural society and the American 
institute of mining-engineers. 
The local committee are actively engaged in per- 
fecting their arrangements for the accommodation of 
the large number of persons which the unusual cir- 
cumstances will call to Philadelphia; and, while the 
contemplated arrangements provide for two thousand 
members of the association, it is earnestly requested 
by the committee, that they be notified as early as 
possible of the intention of members and their fami- 
lies to be present. All members who intend to be at 
Philadelphia should therefore notify the local sec- 
retaries at an early day, and at the same time give 
their addresses where the ‘ Local cireular’ will reach 
them, if they are to be absent from their permanent 
homes during the summer. Definite information in 
relation to lodgings and transportation will be given 
in the ‘ Local circular,’ with much other important 
information. 
A series of receptions will be offered the association 
and its guests, including one at the Academy of mu- 
sic after the president’s address, a reception at the 
Academy of fine arts, a garden party at Haverford 
college, and a microscopical exhibition at the Acade- 
my of natural sciences. The botanical section of the 
Academy of natural sciences will hold at the academy 
a special meeting for botanists. There will also be 
visits to the International electrical exhibition, the 
