58 REPORT—1848, 
On some Properties of Alumina, By R. Puiiuirs, RS. 
It has been observed by Wittstein, that the precipitate which is obtained from the 
persulphate or perchloride of iron, if kept for a great length of time in water, loses 
almost entirely the property of being soluble in acetic acid. Mr. Phillips had noticed 
a similar phenomenon with alumina, arising without doubt from the action of the 
cohesive forces. Whereas the sesquioxide of iron requires one or probably two years 
forthe production of the effect, alumina undergoes the change partially in a very 
short time; the precipitated alumina does not, however, assume a crystalline ap- 
pearance—stated to be the case with the cohering sesquioxide of iron. IJf the pre- 
cipitated alumina is kept for two days moist and in the solution from which it was 
precipitated, even sulphuric acid does not immediately dissolve it. Experiments 
were brought forward in proof of this fact. It was also shown that the interposition 
of magnesia or of carbonic acid prevented the alumina from cohering. 
On Common Salt as a Poison to Plants. By W. B. RANDALL. 
In the month of September last, three or four small plants in pots were shown to the 
writer, nearly or quite dead ; and he was at the same time informed that their destruc- 
tion was a complete mystery to the party to whom they belonged, and that Dr. Lindley 
had expressed his opinion, from the examination of a portion of one sent to him, that 
they were poisoned, Having searched in vain for any strong poison in the soil, and 
in the plants themselves, he inquired more minutely into the circumstances of the 
case, and found that these were only specimens of many hundreds of plants both in 
the open air and in green-houses (but all in pots) which exhibited, in a greater or 
less degree, the same characteristics, The roots were completely rotten, so as to be 
easily crumbled between the fingers ; the stems, even in young plants, assumed the 
appearance of old wood; the leaves became brown, first at the point, then round the 
edge, and afterwards all over, while the whole plant drooped and died, At least 
2000 cuttings in various stages of progress, and 1000 strong healthy plants had been 
reduced to this condition, including different varieties of the fir, cedar, geranium, 
fuchsia, rose, jasmin and heath. The sight of this wholesale destruction, coupled 
with the fact that all the plants were daily watered from one particular source, sug- 
gested the conclusion that the cause of the evil might be found in the water thus used ; 
and this was accordingly examined. It yielded the following constituents, making 
in each imperial pint of 20 fluid ounces, nearly 93 grains of solid matter, entirely 
saline, without any organic admixture :— 
Carbonate of lime...... nipeataae aeteee 0°600 
Sulphate of lime ...c...csseccsceeeeee 0°462 
Chloride of calcitm.....<ccccsccseoss 0°200 
Chloride of magnesium .:.......++- 1°252 
Chloride of sodium ........++. eceae 6-906 
9°420 
The mould around the plants, and an infusion of the dead stems and leaves also 
afforded abundant evidence of the presence of much chloride of sodium, Further 
inquiry showed that the well from which the water was procured had an accidental 
communication, by means of a drain, with the sea, and had thus become mixed with 
the salt water from that source, and had been used in this state for some weeks, pro- 
bably from two to three months. From about that time the plants had been observed 
to droop, but it was not until nearly the whole of a valuable stock had been destroyed 
that any extraordinary cause of the evil was suspected. To place it beyond doubt 
that the water was really the cause of the mischief, twelve healthy fuchsias were pro- 
cured from a distance and divided into two parts, half being watered morning and 
evening with the water in question, and the others with rain-water. In a week the 
six plants watered from the well had turned brown and ultimately died, while all 
the rest remained perfectly flourishing. Assuming from these facts that the com- 
mon salt in this water was the chief cause of the results described, it is proved that 
water containing about seven grains of salt in each pint is, in its continued use, an 
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