120 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
The simplest example is that of “ carmine,” which is exactly balanced 
by 38 units of red. 
“ French mauve ” is balanced by 8 * 4 units of red, • 6 units of yellow, 
and 6*8 units of blue. Here we have *6 units common to the three 
colours, therefore we find as a first result * 6 neutral tint units, viz. * 6 
units of black. We have left 8 '4 — -6 = 7*8 units of red, and 6*8 — 
• 6 = 6*2 units of blue ; but as red and blue form violet, 6 * 2 units of 
violet may be taken out of the 7 * 8 units of red and the 6 * 2 units of 
blue, leaving as a remainder 1 * 6 units of red. The total result is, 
therefore, 6 * 2 violet + 1*6 red -f- * 6 black. 
Another comparison result is of interest. “ Ivory-black” is balanced 
by 10*6 units of red, 9*2 of yellow, and 11*0 of blue. Proceeding as 
in the former case, we obtain 9 • 2 units of black, 1 • 4 of violet, and * 4 
of blue. “Lamp-black,” however, gives 9*2 units of black, 1*4 of 
violet, and 1*9 of blue. There is, therefore, a difference between 
“ ivory-black ” and “ lamp-black ” amounting to 1*5 units of blue. 
The recognition and measurement of such a difference would not be 
possible with a spectroscope. The economic value of this instrument is 
great ; for example, the price of flour, which is dependent on its colour, 
can be indisputably fixed by the “ tintometer ” ; and the percentage of 
carbon in steel can be determined by inspection, without the trouble of 
a difficult chemical analysis. 
Perhaps microscopists will be more interested in the values obtained 
from drinking water. A thickness of two feet from a chalk well gave 
*14 green, *24 blue; when filtered it gave *29 green, *05 yellow; 
when distilled 37 green, *15 yellow; but after aeration with C0 2 it 
gave *16 green, -24 blue. The restoration of the blue by means of 
aeration is an interesting result. 
A thickness of 2 feet of river water, taken above a sewage outfall, 
gave * 5 green, • 7 blue ; but two inches of the same river, taken below 
the sewage outfall, gave 1 • 9 black, 1 • 4 yellow ; this when filtered gave 
•44 green, *86 yellow. 
After such examples it will be needless to call attention to the 
scientific value of the “ tintometer,” which is so thoroughly and clearly 
explained in Mr. Lovibond’s book. 
Patents for Inventions. — The Comptroller-General of Patents, 
Designs, and Trade Marks has submitted to us a volume dealing with 
“ abridgments of specifications ” of Class 97, Philosophical Instru- 
ments,* for the years 1877-83. A glance through it is sufficient to 
show that it will be of much value to the microscopist whose experience 
leads him to suggest what ho thinks to be an improvement in our 
favourite instrument. 
B. Technique.! 
Microtomist’s Vade-Mecum. j — Mr. A. Bolles Lee is to be con- 
gratulated on the appearance of the third edition of his now well- 
* London, 1893, sold at the Patent Office Sale Branch, 105 pp., with figs, in 
text. 
t This subdivision contains (1) Collecting Objects, including Culture Pro- 
cesses; (2) Preparing Objects ; (3) Cutting, including Imbedding and Microtomes; 
(4) Staining and Injecting: (5) Mounting, including slides, preservative fluids, &c. ; 
( 6 ) Miscellaneous. J London, 8vo, 1893, viii. and 509 pp. 
