290 REPORTS ON THE STATE OF SCIENCE. 
been applied for making lead compounds ; for example, lead tetraphenyl 
is obtained from lead chloride : 
2PbCl, + 40,H,MgBr = Pb + Pb(C,H,), + 4MgC1Br 
The method has been very extensively applied, more particularly by 
Pfeiffer, for the preparation of derivatives of other elements such as 
mercury, thallium, phosphorus, arsenic, antimony, bismuth, and platinum. 
Kipping! has made a special study of silicon compounds, and by 
aid of the Grignard reaction has prepared d/-sulphobenzylethylpropyl 
silicyl oxide 
20°5 
C,H,  ©.H 
| | 
SO,H.C,H,.CH,.Si—O—Si. CH,.C,H,.SO,H 
| | 
C,H, ©,H, 
and obtained evidence of the resolution of this compound into optically 
active components. Incidental to this work a number of silicon compounds 
are described, such as phenylethylsilicon dichloride, C,H,(C;H,)SiClL,, 
phenylethylpropylsilicy] chloride, C,H,(C,;H,)(C,H;)SiCl, phenylbenzyl- 
ethylpropylsilicane, C,H;(C,H;)(C,;H;)(C,;H,)Si, — benzylethylsilicon 
di - chloride, C,H,;(C;H,)SiCl,,  benzylethylpropylsilicyl — chloride, 
C,H,(C,H,)(C3H,)SiCl, &e. 
Secrion II, 
Preparation of the Grignard Reagent. 
It is of paramount importance that the materials used in the prepara- 
tion of the Grignard reagent should be as dry as possible. The following 
description of the preparation of magnesium methyl iodide is given by 
Grignard. The magnesium (24 grams, 1 atom) is placed in a round- 
bottomed flask to which are attached a dropping-funnel and a reflux 
condenser. Methyl iodide (1 mol.) is mixed with an equal volume of 
anhydrous ether and 25-30 c.c. of the mixture added to the magnesium. 
After a few minutes a vigorous action takes place, and at this stage 
200-250 ¢.c. of anhydrous ether are added ; the rest of the mixture of 
methyl! iodide and ether is then gradually added by means of the dropping- 
funnel. Finally the mixture is warmed if necessary—that is, if the 
magnesium has not already been all dissolved. Under these conditions 
one obtains an almost colourless liquid, and there. is practically no sedi- 
ment. 
In preparing magnesium methyl iodide in much smaller quantity than 
indicated by Grignard in the preceding description, the magnesium may 
be placed in a round-bottomed flask, connected with a condenser, which is 
provided with a tube, containing calcium chloride and soda lime. The 
mixture of methyl iodide and about four times its volume of ether is then 
added in one lot to the magnesium. The action is moderated, if neces- 
ary, by immersing the flask in ice-cold water. 
The following points regarding the preparation of the reagent may be 
noted :— 
(1) Magnestum.—Powder, ribbon, or filings are employed by various 
1 Trans, Chem. Soc., 1907, 91, 209, 717. 
* Revue générale des Sciences pures et appliquées, 1903, 14, 1041. 
