June 18, 1914] 
NAT ORE 
415 
millimetre in diameter. The magnetic field of about 
160 was produced by coils, and the magnetisation 
measured by the magnetometer method up to tempera- 
tures of 800° or goo° C. The results show that the 
changes of conductivity and susceptibility occur to- 
gether, and that both are due to gradual changes of 
the properties of one of the phases rather than to any 
change of phase of the constituents. The second 
paper, by Messrs. H. Takagi and T. Ishiwara, gives 
the susceptibilities of a large number of minerals and 
igneous, aqueous, and metamorphic rocks, tested by 
the non-uniform field method up to fields of 2600. 
In general, igneous rocks are strongly paramagnetic, 
and their susceptibilities decrease with the field, while 
the other rocks are weakly paramagnetic or dia- 
magnetic, and their susceptibilities nearly independent 
of the field. 
Bu.LietIn No. 42 of the experiment station of the 
Hawaiian Sugar Planters’ Association contains an 
account by Mr. Noél Deerr of an experimental study 
in multiple effect evaporation. From these experi- 
ments it appears that the temperature difference in the 
first cell is a rough index of the rate of evaporation, 
and that the vapours in a multiple effect evaporator 
are superheated. The heat economy of quadruple 
effect evaporators as found in practice compared with 
a computation on ideal lines lay between o-8 and o-9, 
the latter figure being obtained with well protected, 
and the former with unprotected, or badly protected 
apparatus. A vertical submerged tube apparatus with 
5-lb. gauge pressure in cell No. 1 (227° F.), and not 
less than 26-5 in. vacuum in the last cell (127° F.) 
should evaporate not less than g lb. of water per 
sq. ft. an hour, with juice entering at 212° F., and 
should evaporate 4-2 lb. of water per lb. of steam. If 
these results are not realised, foul heating surfaces, 
too slow evacuation of condensed waters, or incon- 
densible gases may be looked for. A horizontal tube 
film evaporator had a much greater rate of evapora- 
tion than vertical submerged tube evaporators. 
THE recent pronouncement of Sir Percy Scott that 
the importance cf submarines has not been fully 
recognised, and that it has not been realised how 
completely their advent has revolutionised naval war- 
fare forms the subject of articles in Engineering and 
the Engineer for June 12. Sir Percy has said that, 
in his opinion, as the motor vehicle has driven the 
horse from the road, so has the submarine driven the 
battleship from the sea. These statements have en- 
countered a good deal of criticism, and neither of our 
contemporaries advocates the interpretation that we 
should discontinue the building of battleships. It 
cannot be said that Sir Percy has adduced convincing 
reasons for the complete change in naval policy which 
he advocates. It has not been established that the 
torpedo, practically the only weapon of the submarine 
boat, would be effective. Again, the radius of action 
of such boats when submerged is very limited, not 
much more than one hundred miles, so that in taking 
a considerable voyage they would have to proceed 
‘‘awash,”’ and would then be subject to attack by 
torpedo-boat destroyers and other surface craft, and 
by aerial vessels. 
NO. 2329, VOL. 93] 
Memerrs of the British Asscciation about to proceed 
to Australia for the meeting in August next, and 
students of geography generally, should examine the 
large scale map of Australia just published by Messrs. 
G. W. Bacon and Co., Ltd. The size of the map is 
72 in. by 56 in., and it can be had in four sheets, 
mounted to fold in neat cloth case for the bookshelf, 
at the price of 25s. The map is constructed on 
Clarke’s Perspective Projection, and the scale is 
I : 2,500,000, or 39:5 miles to the inch. Rivers, lakes, 
and similar physical features, are shown and named 
in blue, while black type is used for place-names, 
mountains, and so on. Roads, tracks, and telegraph 
lines are marked in red. Inset maps on the same 
scale are provided of Tasmania and Papua. The map 
is also published mounted on cloth with rollers, in 
which form it will prove very useful in the office and 
study. 
Mr. S. J. BarNETT writes from the Ohio State Uni- 
versity, U.S.A., to say that the word “size” in the 
penultimate line of the second column of p. 109 of the 
current volume of Nature, on which a letter from 
him is printed, should be ‘‘sign.”” We have examined 
Mr. Barnett’s original MS., and in view of the in- 
distinct character of the handwriting understand how 
the misprint occurred. 
OUR ASTRONOMICAL COLUMN. 
Tue New ZeALAND Soar OsservaTory.—In an 
address to the members of the Wellington Philo- 
sophical Society, by the president, Dr. C. Monro 
Hector, the subject dealt with was the present state 
of affairs as regards the Cawthron Solar Observatory. 
Referring first of all to the approval of all 
the leading authorities in both Europe and 
America for the establishment of such an_ ob- 
servatory, he points out the suitability of the neigh- 
bourhood of Nelson as the site. The records show 
that this region has 20 per cent. more sunshine and 
33 per cent. less rain than at the Kodaikanal Observa- 
tory in India. Several excellent sites about Nelson 
are available, but that on the Port Hills, within easy 
reach of the town, has so far proved the best from 
an observational point of view; if this be eventually 
selected, it will be a means of saving much money in 
initial outlay and running expenses. Mr. Thomas 
Cawthron has promised the 50,oool. for a beginning, 
being the estimated minimum for establishing the 
observatory on a continuous and permanent basis; a 
suggested deed of trust has been drawn up, and a 
suggested board of trustees has been submitted to him 
and approved. The proposed constitution of the board 
is as follows :—Mr. Thomas Cawthron, one member 
nominated by each of eight institutions, the Govern- 
ment Astronomer, and two others elected by the rest 
of the board. 
Tue PosITIONS OF VARIABLES AND ASTEROIDS Dis- 
COVERED AT THE LoweLL OssEervatory.—Bulletin 
No. 61 of the Lowell Observatory contains a com- 
munication by Mr. C. O. Lampland with reference to 
the positions of variables and asteroids discovered on 
photographs of star fields taken with the 4o-in. re- 
flector of the Lowell Observatory. During the past 
year about 800 negatives have been made and 
examined, and measures were made with a Zeiss 
comparator equipped with a Blink Mikroskop. All 
the areas were photographed in duplicate, and the 
exposures were from two to three days apart on the 
average. The settings at the telescope were made on 
