TRANSACTIONS OF SECTION B. 707 
instead of the nearest whole numbers as has beencustomary in all these cases, with 
one exception, namely, chlorine? The temptation will be great, especially when 
we become aware that in the majority of cases the error introduced will be less 
than the ordinary experimental error. The example of platinum at once presents 
itself, without concerning ourselves about the special value for this element used 
by the potash makers for reasons of their own. But comparing the result of 
employing the old rounded-off numbers with that of using the more exact values 
calculated on the O=16 scale, it is interesting to see how little is the effect on the 
percentage composition of potassium platino-chloride deduced from the formula. 
Percentages calculated from | 
— Difference 
K=39'15, Pt=194'8, Cl=35°45| K=39, Pt=195, Cl=35'5 
Potassium : 16118 16°049 069 
Platinum : 40°099 40°123 024 | 
Chlorine : : 43°783 43°827 “044 | 
100-000 99°999 
There are some chemists to whom anything short of scientific accuracy is 
distasteful. It would be interesting to know whether in their daily work they 
use, for example, the number 14-04 instead of 14 for nitrogen, and what is the 
extent of experimental error they admit in analyses of nitrates or ammonia salts, 
of nitro compounds, or of organic matters by Kjeldahl, or any other recognised 
process. The composition of nitro-benzene may be used as an illustration. The 
percentage of N derived from the formula when C =12, H=1, N=14, O=16, is 
11:38; while if C=12, H=1:01, N=14:04, and O=16, the result is 11-40, a 
difference of ‘02 per cent. 
It is also usually forgotten that the values arrived at in all the best determina- 
tions of atomic weights are obtained under conditions which cannot be observed 
in daily laboratory practice, the weights, for example, being usually reduced to a 
vacuum standard. Hence the adoption of the numbers regarded as the most exact 
does not necessarily contribute to the exactness of ordinary analytical operations, 
however carefully performed. 
A little common sense is required in all such matters, but it should be the 
common sense of the chemical world, and not the diverse fancies of individuals, 
and uniformity of practice would tend greatly to the general convenience. The 
only chance of arriving at such uniformity is to submit the question to discussion 
first at such meetings as those of the British Association and the Chemical Society, 
and subsequently at an international gathering such as it is proposed to hold in 
Paris next year, On such grounds I support cordially the chief proposals brought 
forward in the communication from Professor F. W. Clarke. 
3. Development of Chemistry in the last Fifteen Years. 
By Professor Geheimrath Dr. A. LADENBURG. 
4, The Chemical Effect on Agricultwral Soils of the Salt-water Flood of 
November 29, 1897, on the East Coast. By T. S. Dymonp, £.2.C., 
and F, HuGues, County Technical Laboratories, Chelmsford.' 
The fact that on the coast of Essex alone some 30,000 acres of land were flooded 
during the high tide of November 29, 1897, shows the serious nature of this 
inundation of salt water. The injurious effect of the salt water on crops is 
1 The original paper, containing the analytical results and particulars of crops, 
will be published from the County Technical Laboratories, Chelmsford. 
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