SCIENCE AND INDUSTRY. 
90 gallons of alcohol (95 per cent.) per ton. As regards potatoes and 
artichokes, the Committee concludes that power-alcohol cannot be pro- 
duced in Great Britain from these sources on a commercial basis, except 
under some system of subvention. Similar conclusions are reached also 
in regard to sugar beet and mangold crops. No satisfactory method 
for the utilisation of peat as an economic source of power alcohol has 
been brought under the notice of the Committee. The opinion is, how- 
ever, expressed that in connexion with researches into the use of peat 
for various purposes, its potential value as raw material for the manu- 
facture of alcohol should not be overlooked. 
LUMINOUS PAINTS FOR LEVEL-CROSSING GATES. 
A proposal has been made to the Institute that phosphorescent paints 
should be used for painting gates and posts at railway level-crossings, 
thus obviating the necessity for artificial lighting at such places. 
Phosphorescent paints, consisting essentially of more or less pure 
sulphides of calcium, strontium, and barium, have been used since the 
eighteenth century. They are more efficient if the impurities consist 
of manganese, lead, bismuth, or uranium salts. They phosphoresce for 
a short time after having been exposed to a bright light, but they are of 
limited value. Recently auto-luminous paints have been made by mixing 
zinc-sulphide with a small amount (about 0.01 per cent.) of radium 
salts, and these, though necessarily expensive, have been largely used for 
illuminating watch dials, keyholes, electric switches, &e. The radium 
on a watch dial is stated to cost about 6d. 
A recent development has been to replace the radium by 
mesothorium; the latter is present in thorianite and monazite, and_is 
obtained as a by-product in the manufacture of gas mantles. The 
cheaper price of the mesothorium is, however, largely counterbalanced 
hy its short, useful life. It may be considered that it will not develop 
its full activities for some months after it has been prepared, and that 
it will cease to be of much use after about five years. Of course, it is 
possible that by that time sufficient advance will have been made in our 
knowledge of luminous paints to justify the scrapping of all such mix- 
tures as could be made to-day. Considerable use was made of these 
paints during the war. Luminous tapes were used to define paths, 
&e., leading to the front line trenches, and raiding parties would wear 
luminous patches on their tunics to assist their identification by one 
another in the dark. 
KELP INVESTIGATIONS. 
In connexion with the experimental work which has been going on in 
Tasmania in regard to the utilisation of bull-kelp, Mr. V. G. Anderson, 
Melbourne, has specially interested himself in this matter, and has 
collated a great deal of information regarding developments in other 
countries, especially in the United States of America. Mr. Anderson 
has kindly consented to prepare a report on the whole question for pub- 
lication as one of the Institute’s bulletins. 
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