SCIENTIFIC SUMMARY, 
427 
saturated with the gas). On diluting this solution with much water, the 
alizarine is precipitated, in almost a chemically pure state, in the shape of 
an orange-coloured flocculent body. A carefully-conducted comparative in- 
vestigation has proved to the author that the vegetable alizarine sublimes 
at between 130° and 140°. The synthetically-prepared artificial alizarine 
requires a temperature of from 280° to 300°. 
The Formation of Ozone during Combustion. — In a recent number of the 
Chemical News it, was stated by Mr. Loew that in a peculiar experiment 
ozone was formed. In reference to this Herr J. D. Boeke has recently been 
performing some experiments of interest. In Herr Boeke’s experiment a 
stream of oxygen instead of air was blown through the luminous flame of a 
Bunsen’s burner into the mouth of a glass balloon, and he really found that 
the air in the balloon had assumed a peculiar odour, and the property of 
colouring blue a mixture of starch paste and kalium iodide. Both changes 
are the result of the formation of a compound of oxygen and nitrogen (pro- 
bably dinitric trioxide or nitric dioxide), not from the formation of ozone, as 
Mr. Loew asserts. The gas in the balloon being shaken with a little water, 
this was unable to colour the kalium iodide starch ; kalium hydroxide, 
however, shaken with the gas, caused a dark blue coloration in the mix- 
ture, after having been acidified with dilute sulphuric acid. It is almost un- 
necessary to add that he had first assured himself by a blank experiment that 
the iodide was sufficiently free from iodate not to cause errors. With 
ferrous sulphate and strong sulphuric acid it gave the characteristic reaction 
of nitrates and nitrites. So when Mr. Loew declares that he was able to 
“ identify the formation of ozone by its intense odour and the common tests,” 
he was a little rash in this conclusion. 
The Carbonates of Ammonia. — In a long , and valuable memoir on the 
combinations of carbonic anhydride with ammonia and water, Hr. Divers has 
greatly extended our knowledge of these oft-examined yet imperfectly- 
described carbonates. From this memoir it appears that there are three, if 
not four, ammonium-carbonates which crystallise from their solutions, and 
that these have a simple, serial relation to each other. They are the hyper- 
acid carbonate (?), the acid or bicarbonate, the half-acid carbonate discovered 
by Bose, which the author shows hits a formula different from that hitherto 
ascribed to it, and the normal carbonate, which the author considers Dalton 
obtained, but which will owe its recognition henceforward by chemists to 
the labours of Dr. Divers. By digestion at a gentle heat with strong solu- 
tion of ammonia the carbonates of ammonium are converted into carbamate 
of ammonium, thus furnishing a very instructive instance of the dehydration 
of the ammonium salt of one of the simplest acids, and this, too, in the 
presence of water. The carbonate of ammonia, in commerce, is very uniform 
in composition nowadays, and this differs from the composition hitherto 
given to it. Instead of being (C0 2 ) 3 (OHo) 2 (NH 3 ) 4 , it is (C0 2 ) 2 0II 2 (NH 3 ) 3 . 
When sal-ammoniac and chalk are heated together the reaction is not such 
as it is represented to be, and the product is not the carbonate of commerce. 
This is a result of the refining process \ the products of the first distillation 
being ammonium-carbamate and water. These are some of the facts con- 
tained in this memoir ; for others, and a mass of minor details, the reader 
should refer to the memoir itself in the June, July, and August numbers of 
the Journal of the Chemical Society. 
